I'm running 10.10 on two very old Dells. I agree that it is a great OS. I also have a laptop on 10.10 that I forgot about. It lives in my backpack that travels with me or my wife whenever we take an overnight trip. I connect an aircard and bingo - on the net in moments without any hotel connection hassle.
I agree, it's a great, powerful, and FREE os with regular upgrades. I've been running it now for almost 4 years and never ever had a problem of any kind. As long as you keep it updated you should never have issues.
I'm an IS Manager, and technology pays the mortgage. I also run XP, and Win7 boxes at home and of course at work. While MS products is required for my work, I much prefer the Ubuntu package for my personal boxes. Heck, I even have it loaded on a thumb drive to boot my work laptop to so I don't have to mess with the company security to use an air card and get to my personal email!