I used one for many months, and eventually got the slightly larger 8310 Curve as it has a full qwerty keyboard. Its just easier to use the qwerty keyboard as compared to the Pearl's truncated keyboard.
Nothing wrong with the Pearl. If the small size of the Pearl is more important than the full qwerty of the Curve, go with the Pearl.
Either will fit easily in your front pocket. The Curve comes with a little leather-ette case, whereas it is additional cost for the Pearl.
Internet usage is not great on any BB. Some sites don't function well, and it can be difficult to navigate, but its still better than not having it.
My provider is cingular/AT&T, and the phone connection quality has been excellent.
See also blackberryforums.com (it was down today, 3/14/08).