I just got a new Treo 750 today
The speed is good enough for web browsing (3G), but the crappy "Internet Explorer" that came with it refuses to load a lot of good pages
I tried Minimo, it's a version of Firefox for a PDA (but very unlike the real Firefox). It froze the first time I tried to run it
, the second time it was better, but also failed to load some of the same sites that Internet Explorer had issues with, and the interface left something to be desired.
Then I tried Opera, I usually don't like Mac (don't tell my IPod please), I must say it was by far the best of the 3, both in picture clarity, page scrolling, speed and most importantly it was loading the pages the other two didn't (except for one page that uses a strange flash).
If you still haven't tried it, I highly recommend doing so