Seasons 3 and 4 are great. They were getting better...but the failing UPN Network decided not to give it another season...and I suggest you skip the series finale...completely...It's crap...It was rushed, badly written, and actually badly acted.

Season 2 was an improvement over 1.

A lot of people just didn't want to give it time to develop after they got better writers/plots for 3 and 4.

When you get up to it...Enjoy the Mirror Universe ep. It's AWESOME.