I'm in the process of downgrading from Win7 to Windooohs10 because a piece of software I use will no longer run under Win7. I call it Windoohs10 in honor of Homer Simpson, "dooh". Keep in mind that you no longer "own" Windoohs10. Microsoft, in their infinite wisdom(?), aka business model to milk things, now calls it a service, so when you use Windoohs10 you are being "serviced". In addition they're trying to make it more like a phone/tablet, Android/IoS, with touch features. If I want that crap I'll use my phone or tablet! Who wants finger prints and streaks all over a nice 27" 4K monitor?
I'll let you know how the "free" upgrade goes. My Win7 is an OEM version I bought for this big desktop. I'm not sure if I can "upgrade(?)" for free or not, because it's an OEM version, but will find out later today or tomorrow. I'm doing a clean install of Win7 on an M.2 drive and will try the upgrade from that while maintaining the original Win7 install on a platter drive until I'm sure Windoohs10 actually registered with Microsoft assuming it upgrades properly.
I'm sure gonna miss Win7.