Personally, I always have a hard time watching Ecchi anime; I just tend to find myself thinking "why am I not just watching actual hentai?"
Redo of Healer was an exception to that, loved that one.
That magical girl dominatrix one that was mentioned earlier was also pretty good, but I again kept finding myself wishing that it was actual hentai so they'd go further.
Yea, the key difference between "actual hentai" and "I can't believe it's not hentai" is if they show penetration or not; much like the difference between an actual porn and a really racy R-rated movie I suppose.