I'm pleased with Windows 10, but then I'm so crazy I was also fairly pleased with Windows 8.x. Did I mention I used Vista for years before that, and completely skipped over Windows 7?
The only thing I use Windows for is to play video games, and Steam, Origin, UPlay, Battle.net and like work just as well. I enjoy that the system is speedier and that there's that window management thingie that finally works and looks a lot like MIssion Control on a Mac.
The best part is probably that it is more capable of basic tasks built-in, without requiring a bazillion third-party little utilities. The one most useful to me is the included Microsoft Print to PDF option, so I can archive Steam receipts and the like easily.
The new Edge browser also doubles as a built-in, windowed PDF viewer finally. (Windows 8.x had a built-in PDF viewer, but it was full-screen Metro only.)
Then it can play even MKV format video files built-in, it even supports the upcoming h265 codec out of the box.
If I remember correctly Windows 7 couldn't even mount .iso disk images built-in, could it? That was new in Windows 8 and another really basic thing to have, like when XP added zipping and unzipping finally.
So more and more you can just get along with a base system and don't have to juggle hundreds of third-party crap, all with different licensing, updating, system requirements, limitations.
I'm also looking forward to taking advantage of Direct3D 12 and the built-in support for the forthcoming Xbox One wireless controller for Windows.
What was no fun at all was the whole upgrade process. It took 5 times for me as well before I got it successfully installed. What fixed it was installing a beta BIOS update for my motherboard, one which was not linked to in any way from the official support pages, and was dated well before Windows 10 was even conceived, but still newer than the latest official "stable" BIOS.
It did simply restore and reboot to my previous system on every failed try (it would proceed until 75%-99% complete on installation), but maddeningly had to redownload the whole thing again and again.