I won't be upgrading
I've been using the Windows 10 preview builds, and they're fine. Certainly MUCH improved over Windows 8! However, there is literally nothing in Windows 10 that I find compelling enough to actually upgrade to it. Not one single new feature is interesting to me. There are performance improvements, but they are all too minor to justify an upgrade.
I'll be continuing with Windows 7 on my Win boxes until the day comes when it simply isn't possible anymore.