season 2 hands down the best. non-stop action in every episode. the constant tension and fighting between all the cast members. the acting. i think the thing about season 3 is that there was too much going on and it seemed to sort of dilute the story telling and the acting. i would say the only other season that can hold its own against season 2 would be season 4.
Season 4: Intense all the way thourgh. Strong inner conflict within the gang, and the cartel was in interesting plotline. Although the ending is a ridiculous cop-out, but did ultimately work out in later seaosns
Season 2: The Nazi's were strong villains. Conistenstly strong throughout with a fantastic finale.
Season 5: Strong character arcs, specifically for Jax. But the main pot was too unfocused. Jimmy Smits was a fantastic addition to the cast.
Season 1: Disjointed first half, but did a great job of introducing the characters, and ended with a much imporved 2nd half.
Season 3: The finale was great, actually the best episode of the show. But other than a few cool moments in Irleand the the season was incredably dull.
Season 6: Bad. The episodes were all extra long, but they were extra long to be filled with long scenes of staring, and brooding. This seaosn was flled with pointless and terrible filler. The 11th episode and the last 10 of the seaosn were good. The rest not so much.