Win10 is still glitchy. In fact it feels a bit like a Linux distro in that manner. For example, the backup and recovery utility in control panel is lifted straight from windows 7, and is even labeled "backup and recovery windows 7". And it doesn't work entirely right. For example, I could easily make a backup image onto a secondary hard drive in my computer, however making that same backup image to a network location aborted with an error about "incompatible file type".
So yea, its nice and has some nice features but it feels unfinished. I've had some other weird glitches like the 12GB it downloaded from my old WHS computer, the logfile it slammed with hundreds of error entries every second (how ya like *THAT*, SSD memory cells!), and some other strange indexing and windows defender settings that don't seem obvious how they work. But overall its workable and the upgrade installation was seamless on a lightly used win7 machine and a lightly used win8.1 convertible tablet/laptop (acer transformer with keyboard).
I still don't trust it enough to upgrade my main computer though. Too much legacy software that I don't trust to work with win10 is my biggest concern.