I remember angel blade, probably the first hentai anime i ever watched =P
The Asagi games are not bad but at the same time I'm not super into them, maybe because they don't play that much into my fetishes and go more for humiliation/degradation themes.
The characters are funny at times but i never found myself particularly caring about them, the story is interesting but they keep too much of a serious tone for my taste and can be a bit repetitive making me want to skip ahead often. Let's say I've only played them because they have been patched in english, otherwise i would not have taken the time to actually read through them. They have good moments and good art, but not even close to inyouchuu!
I can see why so many people like them though, I wonder how will they shake up the formula with asagi zero,.... if it ever comes out.