I don't use it because I prefer vanilla. QTP3 is too grainy and "filter-fied" for my tastes. I think you lose an element of cohesive art direction when you use QTP3.
However together with the vanilla textures and the parallax mapping, I use several other textures replacer:
improved trees and flora, hires oblivion textures, improved fruits and meats, improved sky, improved signs, low poly grass, real waters, awls, raevwd, and many others.
...now I wonder how much of the original Oblivion can still be seen in my game :facepalm:.