I dunno...
For me there is a certain appeal in not holding back when it comes to movies.
So many others are on the fanservice train too, but they all try to maintain a facade of being something else. Usually leads to a bland and boring experience.
Qwaser does not do that. It is totally open about being a perverted show and it uses the freedom gained from this to do things in more awesome and extreme way. I respect it for that.
btw. Qwaser is not the only show like this.
I'd say you can rougly divide all fanservice shows into two categories, based on how hones they are with themselves.
honest, mostly awesome:
Qwaser
Hagure Yuusha no Estetica
Ichiban Ushiro no Daimaou
Sora no Otoshimono
Highschool DxD
Queens Blade
not honest, usually boring:
Infinite Stratos
all shows containing "Onii-chan" in the title
all shows containing "Imouto" in the title
Medaka Box
Dog Days
Ebiten
lots of other shows that are easily forgotten