I think this season was very good, though I do think they tried to cram in too much detail into too few episodes (Ymir's backstory, Krista's backstory, titan origin, titans within the walls, on and on). I wish they'd had as many episodes as the first season; maybe then we would've gotten to enjoy the careful, paced out dispatch of details we got in Season 1. Nonetheless, very good season. Favorite parts:
The Colossal Titan falling apart on top of Eren
Erwin continues being a bad ass leader even when his arm has been bitten off two seconds earlier
Scenes showing cadets in training (I loved these in S1, and thought the winter training and combat training shown this season was good too)