Having never played with the III, i can't really comment other than to say I love the Garmin V. The more i use it, the more little subtle cool things and shortcuts i find. I used it this weekend plenty... namely to find the Ghost Town geocache down near San Jose... check out my pics!

The only negatives i've found are that the screen can be a little hard to read in the car if it's not mounted at the right angle, and that the screen redraw can be a little slow... all stuff we've hashed over in this thread already. But the size and low price makes up for it's negatives. I pocket it and walk with it all the time. Someone told me they saw one online for $320 the other day!

The battery life is pretty good.. supposed to be 25 hours without the backlight. I haven't left them in long enough to have them run out since i rechard my NiMH batteries after each geocache. The last firmware upgrade added support for NiMH and a couple of others as well as the NiCads and Lithium Ions.