Well, I mostly like Windows 10.
I disagree with the previous poster about Windows 10 looking like '95, I think he doesn't actually know/remember what 95 looked like. But I'm not 100% keen on the minimalistic/no black icons and overall styling. One of the biggest issues with the latest version of Office is how hard it is to differentiate the buttons and tabs.
I'm not a big fan of the start menu, as it makes finding things that I know the location of things that I know where they're located sort of difficult, but makes finding things I don't know the location of easier.
I also dislike the way settings/control panel are getting meshed/split apart/hidden, they're making it take more work for the people who know how computers work to use them.
I'm probably still gonna use ClassicShell to bring back a proper but updated Windows 7 start menu, and in reality, MS should let us choose/customize it to shutup most of the ranters about how bad Windows 8/10 is.
I like the idea of what Cortana represents, I think she just needs to get better and be able to do more things, and seem a little more realistic, like a REAL Personal Digital Assistant. Maybe like, have personalized Cortana accounts that can be used across devices (I'd get a Windows phone with Cortana if she also knew my PC and stuff, have her take dictation, even set up appointments with other people for you, like be able to hold "that level" of a conversation.) and can learn about you, ect.
I haven't done anything really serious with my Windows 10 system yet though, but I still look forward to upgrading my Windows 8 ones when it comes out. I just hope upgrading a system won't completely **** everything up.