As far as mecha/super robot/whatever shows go, I enjoyed this quite a bit.
The show was ridiculously over-the-top from the start, but towards the end it was just ridiculous, juggling universes around and other such misplaced antics. I feel that the show took a major dive sometime shortly after the AS started invading (I guess this is what we call a train wreck
).
Killing off Kamina early was, of course, a necessary move since Simon is the protagonist, but it also established a sense of "people will die here" - and they did not limit the killing to side-characters only, which is commendable.
Enough has been said about the epilogue already, but I didn't like it either (nor the resigned, bittersweet ending itself). My major regret is that we did not get to see more of the transformed Boota (well, and that Nia was killed off).
The soundtrack was above average, although I did not find it too special. El Cazador had (imho) the strongest soundtrack this season; GL only had a catchy OP and one or two decent insert songs ('fight the power', etc).