My W10 thoughts...
I joined the preview program back whenever it was to test streaming from XB1, so I've had it since that feature launched as part of the two preview programs. It was buggy as hell, Edge just would flat out not work sometimes - gives weird error messages and not load webpages, it wouldn't be able to open .docx files in Word 2013, it wouldn't always detect my NAS and required reboots to recognize it, and WTF is the point of these app things to the left of the screen?
I finally got the retail version, which took longer to download and install (significantly longer to install than the preview), but I had to do it by manually searching for updates. Why? So, my thoughts on the current retail version:
Xbox App - Yeah, there's nothing there.
Xbox Store - Yeah, that's confusing. It looks like it's full of mobile games, but then some of them show Xbox covers and look like maybe 360 games? There's nothing AAA or new in there.
Account Management - This is annoying as hell. My local account has admin rights and no password because my GF also uses this computer (its our HTPC) to watch whatever and do whatever. W10 doesn't like that one bit. It wants everything to be tied to a Microsoft Account, which means it keeps 1) Asking me to log in with my microsoft account, 2) asking me for my microsoft account password, 3) asking me to create a pin to log in with that account instead. Except it doesn't remember the PIN! Each time I switch users between various microsoft accounts and the local account, I have to go through the entire process again. I really don't want to leave my microsoft account logged into the system because that gives access to - my microsoft account! Yet, in order to get W10 to fully function, you need more than a local account apparently.
Edge - still borked. Sometimes it simply doesn't work and instead of pulling up a webpage it just displays a bunch of gibberish. It's not even like broken java script, I have no idea what it is.
WiFi Sense - keeps telling me I need to configure the WiFi sense feature. Okay, great. Except this PC has no WiFi functionality. There doesn't seem to be an easy way to let W10 know that it isn't "configured properly" because it doesn't exist!.
Outlook - another annoying notification that keeps popping up telling me that it isn't properly configured. Well, great. I can properly configure it by giving it my credentials. and then anybody using the computer can read all my associated emails!
I guess there's some way to turn these notifications off, but maybe there will be an important notification that I actually care about at some point?
The integrating of the microsoft account into the OS is really irritating considering it appears that with only a local account, you lose a great deal of functionality. It gives the same "Your account needs to be "fixed" message, and in order to fix it, you are required to create a password or use a MS account.
Let me use my computer the way I want, MS!