Greed detected.
He's not greedy, the greedy one is the developer for giving more features by paying for a 'free' software.
On other hand, GameBooster is helpful, the GameBox isn't working well with DRM's if at all (Only works for BFBC2 here..) but for the games you can run through GameBox, try running them in GameDesktop, it's a charm.
Also, the results vary. On BF3, I get no changes, on BFBC2, I get FPS gain, finally on Minecraft I get FPS loss.