I have a Treo 700p, before that I tested out three different blackberries.
The blackberry from T-mobile was the best one out of all of them. The blackberry has much better battery life, is much easier to operate because of the wheel on the side, and is much better for email.
Unfortunately I couldn't get any of the blackberries to work as a modem for my laptop, which is important when travelling.
So I had to go with the Treo because of that one feature. It's clunky and slow and if you use it at all during the day the battery will run out before the sun goes down, so you'll definitely need to bring the charger with you.
The only upside to the Treo for me is that the web browser is much better than the blackberry browser, I can surf sites like GFY and they display properly on the Treo, it was all jacked up on the blackberry.
I also really liked the motorola Q.....very small and light, with the wheel on the side like a blackberry and a very nice display. However you can't use it as a modem either
