OS really doesn't matter that much for mining. Just use whatever you are most familiar with. I would recommend windows or a Linux distro because those have most of the mining software first.
Many Linux distros are considered to be more stable, but I would think that the gpu drivers are way more likely to crash than the OS when mining.
I've read a lot of complaints about Linux AMD drivers crashing, can anybody comment on that point? Quite frankly, the Windows drivers crash too so it might be an empty comparison, just curious.