We finished up a rewatch of the show a couple of days ago. I think my main takeaway this time around is how good the last season was. S6 has very few episodes I don't like. (Probably the second to the last with the child rapist was my least favorite - too dark for this show, imo. Also didn't love the Russian roulette one, though the owner of the escort service and Colby helped.)
Mainly I liked how the characters evolved and how neatly they wove the new CalSci geeks (like Otto Bahn) into the FBI crime solving, so Charlie and Amita can move on without leaving them in the lurch.
Also, the return of Roger Bloom, John Buckley and several Ian Edgerton appearances didn't hurt. 🙂