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.