I specifically talked about the difference between Windows 7 and 8, because that's one case where I don't think anyone could disagree.
I personally feel that 7 is still a better system than 10, but I acknowledge that other people could make a valid argument for the opposite.
My 2011 Macbook Air is still on 10.8. Partially because it has a 64 GB SSD with not enough free space to upgrade, but also because there is absolutely nothing in newer versions that would make it better, and plenty of things that makes it worse.