I used the drivers that came with the Xonar CD (which contained both Xp and Vista), but obviously not 11, hence I don't know and can't make judgements about 11.
At that time, I had just D1, but later upgraded to the more advanced Xonar D2, The sound on Vista was fantastic, on XP and 7, very similar to what we were listening in the 80's terrible cassette walkmans. or similar to the garbage mp3.
On Vista, I always choose 192Khz, of course not 44, and 44 is more like for partially deaf people, the ones who have nothing to lose in the terms of quality anyways.
I served in the artillery, my hearing is damaged, and even I hear the clear difference in favour of Vista.