All of the "newest" blackberry devices have been announced/released, theirs currently nothing on the shelf in the way of rumors for new devices, maybe a US carrier will be grabbing the 8120 (NO GPS) at some point in time soon, but thats a pearl based device,One thing tomdick missed is that the 8320 does NOT have GPS out of the curve series the 8310 is the only one with GPS, so maybe your needs would be better addressed by finding an unlocked 8310.
Google Maps and Telenav (I need both...just in case) work FLAWLESSLY (and it quickly (about 10 seconds after I initialize nav) 'finds me' to within 3-6 meters of my actual position.
Go for it! Crack doesn't always necessarily kill....but I wouldn't recommend trying to smoke your Berry. XD
The GPS has saved me quite a few times, but I have only used the Blackberry Maps program. I recently downloaded Google maps and by what I've read, it is a great app, probably even more so than the BB Maps.