I don't think Gamespot gave the PC version a fair review... see why.

User Rating: 7.5 | Brink PC
Brink is by no means a masterpiece, but Gamespot's review of it is a copy of their review of the XBox version, which apparently had all kinds of glitches and connectability issues upon launch. I have played over 10 hours of the PC version online and have only once encountered a lag issue. The graphical complaints the review makes did not arise in my experience, and I haven't had the reviewer's frustrations about the game's freestyle moving mechanics (known as SMART). There are occasional moments when you don't quite make the movement you were hoping for, but these are very rare in my experience; I think the whole SMART system works surprisingly well and can be a lot of fun. The game's biggest weakness is questionable AI, and there can be some frustrating bottlenecking in certain choke points on a few maps.
But the game has a lot of positive aspects that outshine the negatives, in my opinion. To begin, the sound is very good, the graphics are crisp, and the visual style is cool. The character customization is really immersive, as well. And although the single player with bots can be pretty frustrating, it's designed as a multiplayer shooter, and when you're playing with and against people, the different tactics available become more important and exciting.
If not at full price, this game should still be tried out and given a fair chance (which it did not at the hands of Gamespot, IGN, and other reviewers).