Problems I've had with Win 10:
1) every time I restart, the scroll orientation of my track pad is reversed (i.e., I have to swipe up to scroll down, a la macbooks). This is probably a driver issue which I hope is fixed soon.
2) my computer no longer recognizes my external monitor, despite installing what I think is every possible driver combo. This may be a driver issue...
3) it caused my office to unlicense itself (but I just upgraded to office 2013 so not a huge deal)
One I figure out how to fix these issues and take my start menu, I'll probably be a fan.