The only hiccup I had was with my Nvidia driver. I don't know if it's the issue that I saw being reported the past few days, but I had to open up my task manager and close everything Nvidia related before I could even uninstall the drivers. Once I did all of that, the newest driver from Nvidia that came out yesterday was able to load up and instlal without issue and I've had no problems since, apart from the usual Witcher 3 freezes/crashes of course
Once it was installed, then I had to go back and find any privacy setting I could see and make sure it was set to not send anything back to Microsoft, which goes with my final complaint below.
For Window 8/8.1 I used a hybrid approach of classic shell to get a start menu like Windows 7 and then the start screen to quickly access groups of icons to get into games, etc. I'm going to try and just use the Windows 10 new start menu/screen to get the same results and see what happens.
If there's one thing I'm not liking, it's the continued push for everything serving ads, not 'owning' anything, etc. In the news this morning I saw that you get big full screen ads in Solitaire and they offer you to pay to get rid of ads either one month at a time or for a year. I doubt I will be trying Cortana on my PC for similar reasons.