Season 3 was nothing short of spectacular. Very tense end season. Apart maybe from one episode that made no sens (Probably more for budget reasons) there was a great sens of continuity.
Season 4 is quite good too (At episode 15). 2-3 episodes series were a good choice in my book. What I really like however is how they tried harder into bringing new camera angles and presentations into the show. It was too late by then, but they could have brought something unique into the realm of scifi...but sadly maybe 3 season too late.
Sad that the first two seasons launch such a shadow on the 3 and 4.