If you're doing popular web-stack programming (python, ruby, node) you'll have a far better experience on a unix-based operating system since much of the tooling is designed with it in mind.

Windows has ports here and there, and there's always Cygwin, but it's going to feel like a compatibility layer the whole time you're using it (especially if you're following guides/stack overflow help).

I've used all three stacks for years and couldn't happier with my latest MBPr (hardware or software wise).