In short: Don't waste your time unless you are a fan of AKB48 and all of their many incarnations. If you liked the first one or thought it was fun, the first 3 episodes will be a good place to stop. Let me tell you why:
I really liked the 1st season, so to me this is an epic case of the 2nd season not being as good. To me the story didn't really focus. the 1st season focused on Maeda and the story was built upon her, but for the second season seemed to focus on some weird story between Nezumi, Center and Shibuya.
I really enjoyed the hardcore yankee attitude in the 1st season. I also really like the inter school competition. This season all the characters were played to seem weak, in fighting and in acting. I did like that they brought back the original Rappapa gang, but they had Minami (yuko's character) appear way too many times. They also seemed to have wayyyyy to much girl love like "are they about to kiss?!" ran through my head a few times.
I didn't like the excessive violence in this season, I know Yankees are beating people to a pulp but they aren't killing anyone. However on a conflicting note, the gang fights are better in this season. The ending made no sense at all, I understand what the writers were trying to do with it, but the "from bad to good" concept only really works when there is some major event that evokes change. For some of the characters there was no catalyst. In short: Don't waste your time unless you are a fan of AKB48 and all of their many incarnations.