A fast and nasty comparo between Mapopolis(Palm) Pocket Streets(Pocket PC)
and Delorme Street Atlas Handheld
Screenshots from the Palm are via Quicksnap and ZGrab;
from the Pocket PC are edited screen captures.
UPDATE: Mapopolis Navigator 2.33 has been released! See below!
Also, Mapopolis has a PC/Win Smartphone port-you can see about that at the Mapopolis site(linked below).
OR(dun dun dun) You can Preview it here!"

Mapopolis 1.5 Pocket Streets  

First we look at the maps.
Mapopolis has "Street Names turned off"; which presents a neater appearance. The color scheme is customizable for class of street, bodies of water, selected items, etc. The green road IS a freeway; but roads are based on use, so lesser used freeways come up in the other colors. In a large map, though, it gives you Interstates more subject to congestion.
The toolbar is along the bottom.

Streets gives you a simpler color scheme, and despite cute shields and stuff; all roads are one color. Tools are also along the bottom.
The arrow box moves you around the map-slowly. To move around Mapopolis, you simply drag the map with the stylus.
 
The main colors in Pocket Streets.
If you tap a road,
addresses and names are shown.
Pity that this is hugely wrong.
That address(which doesn't exist)
would be at the southern end of this road,
which is Ohioville Road
and only "CR 22A" for about a mile.

Tools screens:

Mapopolis brings up the tools screen if you tap the lower right icon on the screen. Not EXACTLY that clear if you don't read the "Get Started" documentation. But the alternate plan is to use the dropdown button in the Graffiti area.

Streets does it with a cascading menu. Tap Tools and the menu pops up; tap an item, and a secondary menu comes up.

Looking for something?

Mapopolis consolidates your options on one screen. A nice plus.
There's a catch, if you don't use accepted abbreviations, you won't get a match using address book.

Streets gives you an individual screen
for each find type.
At the bottom, you can enter your address-"Block Recognizer" is on, which does Graffiti better than Graffiti. The Tungsten 2+'s use Graffiti 2 which is a little more user-friendly.

Well let's find something!

Mapopolis starts giving you choices from the first letter-not a bad deal if you know only a part of a street name. If you input a full street name that exists in more than one location; you'll get all choices. Catch(in 1.5): You have to know the local municipalities
(Towns, Villages and Cities in NY).

Streets makes the choice for you. Problem here is that it's wrong. The screen here is the result of the request for "Johns Estate Road" and that's an actual street address, Streets doesn't correctly identify the road, however, so you may end up way off course looking for Granny's house. This happens a LOT.

  Mapopolis gives you a better deal. Most of the time, you'll get this niffers lil box with a gob of info. And in the main, it's going to be right or at least close. Mapopolis disclaimers this saying the little house is an “approximate location”-which it is, but close the right area, mostly.
  And then you have routing!
This is somewhat useful to me in my work-though not always,
since Mapopolis may use roads that
I’m not allowed on w/my work truck(parkways).
It's fun to play with just the same.
The zoom function allows a handy overview of your route.

Here we have freeway junctions.

Mapopolis gives you ramp directions(and one way streets, too), as well as fairly accurate naming. The latitude and longitude, too, if you like(that's switchable) Look at the Kingston Roundabout: That’s an accurate depiction. Local roads can be switched off at any zoom level.

Streets shows the old Traffic Circle configuration, even though the map is from the 2k4 version. Now you get all those switchable points of interest(also available in Mapopolis after v2.2); which may be useful if you're not local.

  More useful if you're not local are localities not listed in Streets. Like East Kingston. This is actually the junction for a road to that area-
but at least you'll be in the right area.
Mapopolis 2.33 update!
And the good folks at Mapopolis must have been listening.
Navigator 2.33 fixes most of my complaints about the program.
The catch? You need a Tungsten 5+-This will run on a Tungsten 2. Slowly. If you don't overrun your RAM.
New maps will run under Mapopolis 1.5.

Now maps are continuous, as long as they all occupy the same folder.
You can load a whole state by selecting it’s MAJOR ROADS map.
You used to have to specifically select that option.
Maps don't need to be in main RAM to run.
On a Tungsten 5/LIFE Drive, you can use the Portrait setting to good advantage.

Zooming in here. You're stuck
with the globby street names :P.
It's a fair trade. You'll note the basic
interface hasn't changed.
The red “north arrow” is kinda punk.
This looks more like the PC version, now as well.
Here’s two LIFE Drive screenshots.
2.33 hasn’t changed up too much
Appearance-wise anyway.
However, compared to the T5,
It’s hella fast
when running maps from an SD card.
Even noticeably faster than a PPC
with nearly the same processor(like the XV6600).
If you run maps from the LIFE Drive,
that’s a bit uglier
(and not recommeded by Mapopolis).
It's sluggish starting up, you get stack overflows,
and it’ll load evey map you have,
regardless of directory,
But surprisingly, you get decent speed.
This is the regular 320X320 screen
with the graffiti area scrolled out.
The LIFE Drive looks similar.
They just changed up to grey.

Points of interest are now included.
but not always in the right place.
This *is* an accurate location for the
petrol station where I fill up my van
and get coffee every morning.
The little blue box across
the street is a restaurant;
but it's on the opposite corner.
Phone numbers are provided.
You can call em up.
The menu hasn't changed.
But the Find option has.
note “Postal Code”.
My big bugaboo with the program,
and more than adequate compensation
for having to deal with the street names.
Once you select an area or postcode;
you make the street/address selection.
Mapopolis Home page
Mapopolis instruction manuals for Palm and Pocket PC(PDF)
These explain the programs and features in greater detail than this page.
DeLorme Street Atlas USA Handheld:

DeLorme also has a PDA Street mapping programme; and it works sort of like Pocket Streets.
You get to pay extra for it, Handheld is a separate program from Street Atlas,
and you get the Streets Application duplicated on your computer just
so you can export the maps; But if you update your original Street Atlas program,
you can export updated or modified maps to the PDA.
Street Atlas USA is at least ported to both Palm and Pocket PC.
You also get routing-with a catch: You'd have to load a huge file to have the feature be useful.
You either need a Pocket PC or a OS 5 Palm. Files are too large to deal with on a OS 4.1 machine.
Accuracy level is similar. It looks better on the Palm. These screenshots suck.
The Delorme search screen-enquiry.
Delorme Search screen results.
Sometimes you get actual relevant results.
Depends how you set the parameters.
Localitiescan't be searched, unlike Mapopolis,
tho ZIP code info is included, you can't search by ZIP.
A search could take a LONG time w/a slow processor.

On the Tungsten 2-Delorme writes maps to your main RAM.
You have no choice in that matter,
You have to manually transfer the maps to your card.
But it's done relatively quickly(on Tungstens).
On the T-5 you could use the file transfer utility
to put a map where you want it.
Redraw rates are 1-5 seconds when reading from the card.
The thing is, tho, that ALL your maps are joined together.
Any large files would take a great deal of time to draw on
a device with a 33 MHZ processor. Streets doesn't do this;
Mapopolis gives you a choice whether you want to join
your maps; the drawback to that is if you have a low-ram
device, you can overrun your RAM fast.
Mapopolis will draw maps already in RAM quickly even on
slow chips.

Delorme Map info screen. The map here covers a much larger area than similar Pocket Streets maps, and filesizes are smaller overall for a map that performs about the same.
From an area map. This is at 10:1 zoom-and it's the map described on the screen above. On a Tungsten it's manageable, but anything less than an OS 5 machine would have you tearing your hair out waiting for the file to load. Navigation is like Mapopolis-You drag the map around with your stylus
(You can also do this in the PC program).
Redraw rates are slower, for obvious reasons.
Welcome to the Joy of Vector mapping. Also the Joy of inaccuracy.
Delorme's accuracy rate is poor.
NY 199 doesn't go this far south, and you have the same old
Traffic Circle(rectangle on the Zoom level 12 map:P)
configuration that went south years ago.
Compare this to the same area in Mapopolis above.
Looking a *little* better here: This is a 12:1 zoom map.
You'll note *NY* 587. Is Delorme getting their cues from NYSDOT?
This is a higher zoom level yet, with mega POIs, one which blocks a street. Delorme's exit descriptions(blue panel at the bottom) are basically useless, and IMHO much worse than Mapopolis or Pocket Streets.
Vector globbiness with DeLorme's nearly invisible indication of a selected item(that teensy little box-compared to Mapopolis' highlighting).
The blue panel tells you the address range of a street you select,
fairly useful, and reasonably accurate.
Delorme also includes Zip Code data but not searching.
The Also-ran: The Rand Mc Nally Palm Card

Bland Mc Bippy came out with a MM Atlas Card back in 2k1: a subsequent release runs on OS 5+ and Pocket PC.
This is meant as a supplement to the paper atlas.
Bland McBippy also makes Tripmaker software,
and you can clip maps with that a lá DeLorme.
The snaps are tiny-remember OS 4.1 is 160x160 screen resolution.
The title screen.
There's a message that scrolls across to
tell you to tap the state you want to see.
Well, not exactly.
Tap any state in a given area, and this menu comes up.
Once you choose your state, then you get to choose the city.
Finally, here's a map. Only minimal shields are shown.
You tap on a road, a dialog comes up asking you to label it.
The arrow circles are *Noted* junctions. Not all junctions
have this symbol-a junction without the symbol has no
information attached to it. You can't even find out the exit number.
In cities this can get really globby.
A labelled road. You can also mark a road, if you like. sort of a primitive
Pushpin function.The yellow road color indicates scenic highways.
Numbered Routes are red(class notwithstanding), local roads are grey.
Freeways are Purple/Red, Tollways Yellow/Green.
You also have an additional function menu that can be
displayed or hidden by clicking the arrow at the upper left.
Pity you can't toggle off the blue rubbish :P
An Urban area(yellow). Maps can be navigated by dragging them with the stylus.
You can zoom in and out by clicking on the scale on the right.
That doesn't increase detail(which is fixed),
but is helpful in dealing with congested areas.
A larger scale map. Along the bottom, you have the routing icon,
and the page coordinates for the paper atlas.
Clicking the US icon returns you to the main screen.
Alaska, Hawaii, Mexico and Canada are not included, BTW.
Click on an “exit” symbol, and you get this screen.
If a name doesn't fit, that's your hard luck. Sorry.

You can pick and choose what *noted* junctions will be displayed,
not all junctions are displayed.
and the criteria for display.
Another way to get around is to use the drop-down menu.

The routing function.
On a 33mhz processor, this takes about 2-5 min, depending on complexity.

So that gives you an idea what these programs look like, anyway...
I prefer Mapopolis for a number of reasons which I think I've explained.
All programs are GPS Capable, by the way.

Mapopolis Navigator 1.5 and Delorme Handheld Streets 2k4 are running on a Palm Tungsten T2 with 32mb RAM running Palm OS 5.2.
Mapopolis 2.2 runs off a Tungsten T5 with 64/160 ram and a MUCH faster processor.
You can download the 1.5 version HERE. It includes a sample map to play with.
New Mapopolis maps are compatible with version 1.5
Screenshots were taken w/Quicksnap and ZGrab; These DO NOT look as good as they do on the actual Palm Screen.
Pocket Streets was run on a mute IPAQ 3835(the previous owner jüted the sound somehow, it didn't click or pEEb or nothin'), running Winblows Pocket PC 2k2 OS(can't get 2k3, cos the original software CD is lost, too :P).
The Winblows Mapopolis page is screen caps from an Audiovox XV6600(cos TREOS suck),edited in The GIMP
The shots on this page were done in Photoshop.
The Screenshots on both pages were captured by Micro$haft's remote CE client.