I'm an owner of the Motorola Atrix 4g since a month, and an owner of the Samsung P1000 Galaxy Tab w/ CM7 since the dawn of human generation :P, and from my experience with both of these droids, I can say strictly that the GPS quality on both of them is a no match for the N900. Don't forget that the ATRIX and the Tab are in the list of symbolic Android devices too.

If network positioning is off in my N900, I can get an excellent GPS lock withing 2-3 minutes if I'm in a clear place, and 4-6 minutes if I'm in the busy streets of my city. If network positioning is enabled, I get a GPS lock instantly, a matter of seconds. This is far the fastest rank of mobile-GPS-signal-acquiring I've ever experienced.

While on my ATRIX, GPS quality is great, once you get a lock. Yes, you can get a lock 5 satellites indoors but most (if not all) Androids require data transfer (internet) in order to get proper GPS signal. I've never seemed yo be able to get a lock on GPS if I'm offline.

I've owned an N97, which had a hardware problem on the GPS receivers so, hopeless!

What is the secret? Is the GPS-related software in Maemo 5 optimised to use every single bit on the N900's GPS module? This maybe the reason because there is only one Maemo 5 device, while there are thousands of Android models which can't necessarily have an optimised software for all different models...
It's a shame NOKIA didn't release proper Mapping and Navigation software for Maemo 5, but I'm looking forward to experiencing the "Drive" on Maemo 6/harmattan on the NOKIA N9.

My Droid (The Original(TM)) has excellent GPS. It seems to get a good lock quickly even if I have data turned off (which I always do). The main thing that puts the N900's GPS over the Droid's is the offline map storage. If the Droid had that, I would prefer it.

Also, interestingly, newer homes in my county are on OVI maps but not on Google maps. These homes and streets are about 4 years old. In some cases Google doesn't have the street drawn in, and in other cases Google has the street drawn in, but not named.

The worst phone GPS I've ever seen is on my wife's iPhone 3G. I have never gotten it to under 100m radius. I looked it up on the Internet, and everybody says it has a-GPS and now I'm becoming convinced that it's tower only. 100m GPS accuracy? Might as well put a red x on a blank screen and say, "You are here."

Sorry. I've been bottling up that particular rant for a little while. My wife just doesn't appreciate GPS accuracy, so ranting to her just isn't the same.

I dunno, N900 is my first device with built-in receiver. With the previous device, an N73, i used an external BT GPS mouse (Royaltek RBT-1000 which i still own). And while that mouse is truly excellent, i.e. failed me only in NYC skyscraper ravines, in contrast i find the N900 A-GPS abysmal in both fix time and accuracying. While being abroad in Amsterdam, without network supplied positioning due to roaming, fix time was almost 10 minutes on the square in front of main station. Maybe i'm just spoiled by SiRF III w/ WAAS/EGNOS... Also the US-bought Samsung Galaxy Tab 10.1 that i had for testing until today was crap in my eyes, and with even longer fix times...

Weird. What "aPp" are you using for mapping?
OVI Maps?
Navit?...
I personally use Sygic, there are many different alternatives for the default OVI Maps out there, but I just can't rely on one.

Depends. Sygic has the unfixed occasional segfault after some time, so if it has to be reliable, it's up to Mappero, modRana and Marble w/ pre-downloaded map tiles if possible.

Man, do i MISS TomTom and especially Garmin Mobile XT on the N73... those were really reliable, but slower.

Yes happened with me before, but it is pretty rare, I mean once per 20 times of use.

Yeah I still have got Garmin Mobile XT on my N97, it was the best mapping and nav software for the n97, I can't remember specifically, but it used some kind of optimisation and software enhancement which made locking a GPS signal on my N97 faster than OVI Maps 3.

The N900 is my first device with gps built in, but I have to say that I'm very very satisfied with it (using Sygic). The lock time usually is under a minute for me outside my house (in the house it locks within 10 seconds of starting Sygic). My brother has a Samsung Galaxy S2 but sometimes the built in gps on that is crap, so he uses the Sygic gps for android which is pretty good, although his signal tends to go every now and then. For me it only happened maybe twice that the signal was lost and couldn't lock again so then i restarted Sygic and all good. I have been using Sygic for more then 6 months now and it's a great gps program.
I also have a program called GPS recorder, it can show how many satellites there are and what the strength of their signal is. There are other features but this is the one I find interesting.

Sygic crash and sometimes even freeze the gps position (much more annoying).
I use it only when I've taught my copilot how to kill it and relaunch it.
But when it works it works pretty well.

In my experience the N900 has a very middle of the road GPS. For driving it's fine. For golfing, it sucks.

With the N900, the Nokia supplied software relies on a data connection, maps will timeout and fail to get a lock without a data connection. Community supplied software doesn't have that issue and the N900 will eventually lock. Generally far slower and far less accurate than my bluetooth gps.

In use, I found the N900 would jump around a lot (poor accuracy), which for driving isn't much of an issue. For anything where accuracy is needed (golfing, geocaching, etc) the N900 isn't very good.

On the android side, I have two devices. My huawei will find a lock within a minute (without a data connection) and hold accuracy to 3-4 meters. My samsung vibrant (on froyo) would lock quickly, but the accuracy would fluctuate between 7-20 meters. Running gingerbread (with hacked drivers) the lock time is a little longer, accuracy is about the same. In comparison, my N900 generally could get a lock in about a minute as well (without data) but varied from 7-30 meters for accuracy, and would consistently jump around.

I really think it comes down to the particular device/os combo, with the N900/maemo being somewhere in the middle of the field.

A bluetooth gps receiver has the advantage of not having users pointing the antenna in random directions all the time, or covering it randomly with hands and fingers all the time ;-)