The Treo Pro is possibly the best choice I've ever made.
As an earlier poster said the Touch Pro is prone to breaking quite frequently. I only had 4 of them myself but out of those 3 the screen went out on 2 and the keyboard went out on the other.
It got on my nerves. I'm not saying the Touch Pro isn't a good phone, it is. Huge screen, great keyboard (that CTRL key was awesome) and just an all around amazing device.
Battery life was a terrible problem though. My first 2 months with one the phone would only last 4 hours on a full charge (I am a power user though). I ended up buying a 3600mah extended battery for it which allowed my phone to go 12 hours with heavy, constant use. It made the phone HUGE though. It was like I was carrying a 6700 again lol.
The Treo Pro just 'works'. No need to continiously flash roms or anything like that. The keyboard on the front of the device is very useful. Like earlier posters I'm just a little bit annoyed by the screen size, but that's not that big of an issue after a while. The battery life is also tremendously better on here. I get a good 8 hours out of it.
Idk what else to say really. I probably sound like an Apple fanboy right about now. LOVE THIS PHONE. Wouldn't mind trying a Touch Pro 2 or Diamond 2 though.
Just my two cents