I began watching OPM 2 without hearing or reading anything about the animation studio's change. I found the 2 first episodes OK, I thought it followed the tone of season 1.
The 3rd episode made me change my mind from "OK" to "kind of boring". We started following many parallel plots and despite various fights and new characters introductions, the rythm was really slow and sometimes frustrating. Episode 6 was the pinnacle of disappointment.
Then, episode 7 was the one who stopped this pitiful fall. I suddenly regained interest in the plot. I can't really tell why, maybe it cut less between scenes, Saitama's costume pumped me up or something.
The last 5 episodes were pleasant to watch : they surprised me, they made me laugh, they got me excited for fights. Like good old season 1, just less intensely.
Aside from this clear difference of interest between episodes 1-6 and 7-12, I had some problems all along the season. First, I felt 0 empathy with Garou, as his motivations and goals remain unclear for me. I just keep wondering what this guy really want and why. His last fight is still pretty cool, but it doesn't save the character. Second, Suiryu. This guy made me laugh but seriously, you can predict what's going to happen to him since his first appearance but they took sooooo much time to build it up, I felt exasperated.
Other than that, the OST is good, the art is not something to puke for (except that odd metal effect they did on Genos and metal knight for example) and the story took an interesting turn.
They've been far more worst animes and far more better too. I don't think it deserves the hate it gets from some people. It's an average season 2 after an outstanding season 1. Really, it's okay.