This is a review from someone who's not a fan of ecchi, but can deal with it.
So straight up, if you're not a fan of ecchi, you're perfectly fine to take a pass on this anime, because while it's decent enough if you're bored, there's definitely better stuff out there to watch.
The art is unique and eye catching (though the limited action sequences are awkward and clunky, epecially in the final episode), the sound is good enough (the music is zany and cutesy; as is the rest of the show), and the characters are OK.
Really, the only thing that you can knock this show on, is that the pacing is just a tad off. While bits of the very start and very end are interesting enough, the middle episodes suffer a noticeable lul; and that's a bit unforgivable in a series that's only 12 episodes long.
The ecchi, while part of the premise, feels kind of almost like a gimmick (it's used and it's not hurt by it, but the story makes equal sense without it), and one you can for the most part ignore. I can say though that, if i were someone who WAS a fan of ecchi, i could see how I could focus on the rest of the positives enough to give it a 7, maayybe an 8, because it's quite good--for an ecchi. (To give it perspective, this is a solid one, probably two notches down from another recent ecchi with an interesting premise, No Game No Life--which, incidentally, is a series good enough to watch as an anime, period). Being that I'm not though, comparing it to all other anime, ecchi and not, I give this about a 6.
Not being a fan of the sub-genre, I stuck around because the premise was bizarre, zany, and interesting enough that I decided to give it a start to finish shot, but ultimately, while nearly everything was tied up by the end, i still felt like it didn't live up 100% to the potential I saw, and the other positives weren't standout enough to make this show worth actively seeking out.
Give it a shot of you're bored and have watched absolutely everything else, otherwise, pick another show.