I think this introduces a whole new group of people to the power of this development environment. It's still Visual Studio at the core, and that's an amazing tool.
I don't really have anything against the open source world, but the people that blindly treat it like a religion and discount Microsoft stuff because it's Microsoft don't get it. I don't mind paying for products that radically make my life easier as a developer. Considering what my time is worth (and therefore what my clients' time is worth), the cost of this stuff is a drop in the bucket.