I'm using one in a win7 32bit system and the other in a win7 64bit. Both have worked flawlessly. I used one of these in an XP system prior to changing the os. There is a win7 issue that requires one to shut off variable cpu speeds as it can cause a popping sound during record, but I don't consider this to be an M-Audio problem. The sound it terrific, especially on hires playback WASAPI Event style. You do need a good editing program for recording, I use Sound Forge for editing, but open source Audacity also works well. JRiver Media Center is used for playback in my music server.
I would say that some setup knowledge is required. People also need to use it for the purpose for which it is designed. It is not a do everything for everyone product.