I’ve purchased 6303 classic 2 months back when my W580i display broke down. The very big plus point with Nokia mobiles are the user-friendly software and menus, 6303 falls in the same line. The metal body looks great and strong. Display is very good, camera picture quality is super (3MP) even under low light conditions (dual flash helps a lot). Voice quality is good, key pad is friendly but bit small. Long Battery life. Got 1GB memory card with the phone, music and video playback is good even though sound quality is not at par with my old w580i, may be because of the special design of Sony Erricson headsets.
Phone is bit heavy, but that is due to the metal body which is scratch resistant but if you drop the phone to the floor. Forget kinetic energy would be too high. Navigation key could have been better (like in blackberry), bit difficult to surf the internet because of this. Also, the surfing speed not fast- it is not a high end phone ;-)
Connectivity to PC seems to be good, both bluetooth and cable works well. Nokia PC suite is user-friendly, things are pretty easy here.
In short, 6303 Classic is a very good buy, it won’t hurt your pocket and your expectations.