Hi,
It seems like a fair question to ask "Which one is more stable?" but as you will learn through expierence you are comparing two different OS. Both OS's can be pretty bad, with a bad administrator. You have to learn, and lots and lots of reading, and learn from mistakes, then you will be able to make the most unstable OS, more stable. For, that very same reason, I like linux better, it allows you to customize it as much as you want to, thus allowing you to make it more stable, and turn off things that you don't want or that could make your computer less "stable, secure, blah, blah." Linux has a very big advantage over the other OS's in the market, and that is US, the community. The linux community offers support and fixes to bug faster than for any other OS, and if something should be changed the developers will certainly hear about it. That's why as linux users, we try to keep this community afloat, by doing things such as helping each other, and also reporting bugs if we find one, posting responses or providing help to newcomers. After, all remember, "dont ask what LINUX can do for you, ask what YOU can do for linux."
Good luck,
pitupepito.