Well, I've only been playing with it for a week now. However, so far, I rather like it. I have the Ultimate 32 bit edition.
1. It's really pretty.
2. The software mixer uses apparently unlimited discrete input and output channels. So, I can, if I were so inclined, listen to a game on headphones, while chatting with a friend playing with me via Skype on my bluetooth headset, while pushing the music from iTunes to my 7.1 surround sound, while watching/recording stereo TV on monitor 2, all on one computer at different volumes, with no crossover. When I receive an instant message, which I set at a lower volume level than the music, the obnoxious "ding" heralding it's arrival is neither deafening nor below human range of hearing.
3. I still can't get over number 2. I mean, come on!
4. The Windows BlueTooth drivers suck, but as long as you have your own BT drivers (hopefully came with your BT device), it works pretty well.
5. Make sure you have a whole bunch of RAM!
6. They've made the array of menus one must navigate to perform the most basic networking tasks simply dizzying. On the other hand, they've added a lot of functionality, too. It's a source of mixed emotions.
7. Did I mention it's pretty?
It's Microsoft, though. Give me a few more weeks, and I'm sure I'll find reasons to hate them. They're selfish and intrusive. I'll change or upgrade something, and they'll force me to reactivate Windows by threatening to lock me out of my own computer. That's one problem I've already run into. I'm sure they'll come up with new and inventive ways to piss me off, though.