From what I've read, Win 10 removes some features that are standard in Win 7, and also removes the option to decide which updates to install (unless you are using one of the upmarket versions).
I'm not sure whether I care about the disappearing features; I'm not happy about automatic updates because I've had to deal with some broken ones (there STILL isn't, as far as I know, a recent competent driver for my nVidia card - I'm using one that's two or so years old. Every batch of updates strongly recommends updating, but I find it hard to work on a black screen with black writing).
I'll wait for the reviews of Win 10. If it does any of the silliness that Win 8 perpetrated, I'll be sticking with Win 7.