I think both seasons are roughly equivalent. I can see the POV of people who really preferred the Roberta arc, but that wasn't even my favorite part of the first season (though I did enjoy it). Each arc manages to have one or two moments that make me go
just for the choreography. Throw in pretty competent storytelling and directing and I think the show has been just as good in the second season as it was in the first. Really, like Shiroth said, it doesn't even really feel like a second season at all - and not just because they continued the numbering from the first season.
I think Deacon's right, Geneon has a hit on it's hands. I can't believe someone hasn't stepped up to license the manga yet.
EDIT: My favorite two arcs (so far) have been the nazi submarine arc and then either the Roberta arc or the Greenback Jane arc - I really enjoyed the all-star lineup the Greenback Jane arc had.
