I thought it was really quite funny. It does a good job executing a fairly generic premise (as noted above), and plays it up for good effect.

This is by far one of the ecchiest shows KyoAni has done, and I think they nailed it in terms of balance, while being completely self-aware. Mostly Mai molesting herself innocently, the others detailing scientifically how she was controlling the bounce of her boobs (and the clinical nature of that discussion was what actually embarrassed her) and the falling down the stairs scene was well executed, between the noble sacrifice to avoid touching her boobs that ultimately backfired when Ruru did the correct thing and prevented any and all injuries for Reina.

While it is good to see Inoue Kikuko playing an Inoue Kikuko Role, I was most impressed with Uesaka Sumire. Her range has really exploded in recent years. Even when her characters sound the same in pitch to a previous one, the tone and delivery of her characters has been different pretty much every time. Compared to the rest of the cast that sound pretty much the way they do in every series they're ever in, Uesaka Sumire is killing it here. She's really talented, to a degree that isn't really obvious at first.