Played it and continue to do so. Its an amazing game!
The good:
- nice campaign story
-get to play as the arbiter
-cortana looks better
-better weapons
-new vehicles
-spiffy new graphics
-MC looks good or 40
The bad:
-some weird graphical issus
-cliffhanger ending
As you can see, the good outnumber the bad, like any other amazing game. The gameplay is amazing. Multiplayer is where its at, if your not beating the campaign for the 100th time. The campaign is fun to play, again and again, don't ask why. I can live with the graphic issues (units may disappear and reappear in cinamatics, or a bitmap of the charcter may appear first, then the detailed version.) but the ending really bugged me. Good ending though, leaves you waiting for Halo 3, but the game seemed to build you up then drop you on your ass.