Season 1 followed the comic and was awesome. Season 2 diverted quite a bit and the quality of the show dropped off. S3 is back to following the comic a little more closely and it's rocking again.
I am current through the first 8 volumes in the comic, and for those who haven't read it, let me assure you it is some of the craziest shit I've ever read. If they continue to roughly follow the comic, this season could be one of the most epic in TV history. And going by the first two episodes of S3, we are well on the way to that insanity. Buckle up, fuckers.