I reviewed both systems on the same platform side by side. I like the GUI interface of NT with IIS, but it's not all there yet. For communications it's Linux. NT is fun, but pricey.
Security is great on both systems.
Programmatically I like windows messaging, but forking is more stable on heavy loads. Once up and running, both systems are unstoppable. Most SSL seems to be with NT at ISP's though. Rob Thiemann Python is in there. You forgot reliability.