Season 3 almost made me quit watching. Those first few episodes are so godawful boring, but, as previously said, it gets much better. Holy fuck is the second half of Season 3 so much better.
Seasons 4, 5, and 6 I think were pretty good, although Season 6 has some stinkers. Season 4, in particular, was really good. The change to their new format really helped the show, IMO.