1. $20 is a steal considering I pre-ordered it and payed the full 60 something dollars for the game for 20 I would buy it for the PC maybe but not off steam only if I get real DVD disk media.
2. I don't know but the 360 community with it is doing pretty good.
3. Depends what kind of player you are. If you like Fallout New Vegas then you may be the kind of gamer who likes to explore more than playing others on line. If this is the case don't expect a lot of exploration in BRINK it's an objective based FPS.