Last weekend I upgraded my PCs to Windows 10. That's 3 out of 9 PCs at home. My main PC (previously Windows 8.1 Pro), my 'backup' machine (an HP OEM server that was running Windows 7 Pro) and an old Samsung netbook that was running Windows 7 Starter. I would usually opt to do a clean install, but for convenience I decided I'd try the upgrade path first. I imaged my previous Windows 8.1 pro machine in advance so I could roll back without fuss if required. The upgrade was pretty much flawless and all my previously installed hardware and software work in 10. A few drivers were updated in the process which defaulted some settings but it was otherwise painless. Since the HP server is just a backup machine, there was very little in terms of hardware or software to worry about, so I didn't even bother to back it up first. That upgrade was even smoother than my main rig since most of the drivers were on default settings anyway. The Samsung netbook failed during the upgrade. On the second pass, I opted to delete all apps and files, since I don't really use it and there was nothing on it I can't replace.This time the upgrade succeeded. I had to download just the touchpad driver from Samsung, and apart from that, again it was pretty much painless. The upgrade leaves behind some large installation and backup folders, which should clean up ok but I haven't done so as yet so I can't comment. So far, so good! Much better than some previous upgrades I've done. Another positive is that my images viewed in Windows 8.1 photo viewer always seemed a lot darker than when viewed in LR, PS or a web browser. I tried to resolve this through calibration but there was always a difference. In Windows 10, or the compatible video driver, that seems to be fixed.