If you want a fast, stable, easy to use operating system Give Linux mint a try. Very user friendly -I told my Gran it's the windows and she has no problem. Also cut down the time I spend fixing it to zero.
As for Win10, I will have to give a spin before I pass judgement. Just deciding whether to wait for it to come out of developers preview or not...
I used to run ubuntu and it was amazing. Set it up so nicely with themes and compiz and stuff it was pure eye candy. Unfortunately the drive it was on crashed so I went back to booting from my windows drive.
Should get another drive to put linux on actually... I just remember after spending weeks researching and learning and fine-tuning that OS to my idea of perfection I got so pissed off when it broke... I couldn't face doing all that work again, trying to set it up to be identical to that perfect build... I just knew I could never get it the same again so I threw the drive in the bush and tried never to think about it again lol