If I may play devil's advocate for a moment: out of fairness to Windows 10, it has gotten a bit better than the RTM release.
And I'd also like to point out that XP wasn't always the "gleaming pinnacle of perfection" that many see it as nowadays; In fact, back in 2003-2004, I recall it was actively despised, and often criticized as being slower than the versions it replaced, namely 2000 and 98 SE (which was still pretty much 100% usable back then). It did improve with time, however, and once SP2 came out and multi core PCs became more commonplace, XP matured quite nicely. It would be nice if 10 would follow the same progression and actually become a mature, decent product, but so far, it hasn't....
Be that as it may, even after almost six years, I still don't like 10, and I won't use it (I actually did try for awhile, but it broke on me, and rather than going through the effort to reinstall, I decided to wipe it and install Linux in its place). Fortunately, because my primary is Mac OS, I don't really have a need for everything to work 100% on any older Windows, thus having the luxury to tinker with and hack up any Windows of my choosing ad infinitum .
c