I got this a while back for like 8 bucks and I really do like it. If you like the battlefield style games, or if you were into the multiplayer from Return to Castle Wolfenstein then there is no reason for you to not pick this up. One thing about this game that I love and that I desperately wish valve would implement is having game sound come from your speakers and voice chat coming from your headset. This game does that very well. Buy it and DEFEND THE DATABRAIN.
For $5, this game is a definite steal. I got it for $6 at Big Lots a while back, ended up sending another copy to a friend. We've been having a ton of fun with it. If you like FPSs, I recommend it.
My old boss and I used to play a ton of BF2142 and we both hated the demo for this to the extent that we gave it a total miss. Everything felt wrong and I was so disappointed. Great deal if you like the game, though.