The first three seasons were pretty great, especially season 2&3 which were excellent. Then the storyline became less thought out even though some episodes still do stand out. But the main problem is with the characters in season 4 and especially 5. The newly introduced characters aren't interesting, there is no cool story around them, the existing characters were dumbed down and became one-dimensional, and the team dynamic went out the window. They are all there in the same scene but the atmosphere is like sitting in the teachers lounge of some middle school during recess. The rating 7 is only there for the sake of the first three seasons.