I write this shortly after finishing season 3. For me, 2-ond was best, 1-st was very good, and 3-rd - too unoriginal, cliche, uninventive alien scenes ... Unlike many I don't think that S3 ep1 was worst. For me worst were S3 ep5 and 6. Partially because not good direction. Fight scenes were just lame, some car crashes too.

I guess, I need to watch again season 1 - if nothing else because I missed song Should I Stay or Should I go - nothing from it in season 3 :-)