It would be very valuable to potential upgraders if the W10 Preview Testers would be so kind as to evaluate W10. On having been so intimate with this OS for months on end what is your overall impression?
It's not without quirks but I'm switching from 7 to 10 shortly after launch. Will it be quirk-free after launch? I doubt it but these are nuisances I'm referring to; it's stable and responsive. You really should install a VM (or swap disks) and try it if you're on the fence. I say this as a person who couldn't suffer Win8.1 for more than a few days and downlevelled the laptop that came with it. Check driver compatibility too; my Sound Blaster X-Fi doens't work on Win10 and drivers won't be available for a few months (using on-board RealTek until then).
I've been using the preview edition as soon as it was available and use it every day. It is almost 100% Microsoft with the exception of Ccleaner, my screen capture and my file manager. I have no problem with it but I really don't use and don't need all the extra stuff that has been added to it. Because of that, I have no intention of installing it over Windows 7 on my other computers.