I've had may problems with wasapi, asio, wasapi event style etc with my hrt ms II when using windows 7 and foobar2000/Jriver.
The usual problems with stutter etc. I used to use windows xp with foobar 2000 and asio which never gave me any problems.
About a month ago I decided to try kernel streaming with 50ms buffer in foobar2000. It has been a revelation! I listen for about 3hours a day and have not heard a single problem, ever. Going back to wasapi it starts playing up again.
If you haven't tried it in foobar2000, it might be worth a try; you may get lucky like I did.
I also play from ram-disk, which (for my setup) prevents any glitches when playing files with different sampling frequencies.
Kernel streaming is bit-perfect, and apparently wasapi is just a wrap around for this that adds extra processing.
I'm no expert, but just thought I'd share my experiences.
Cheers.