Edit: Too bad it hasn't been opensourced. Lack of being opensourced is a death sentence for any tool.
Actually, I didn't always believe this, I saw in the time around longhorn, that visual studio was miles ahead of anything else with its almost bugless, very fast, easy to install tools that had every library preconfigured to provide autocompletion and documentation. I was surprised that the majority of windows programmers I knew were using open source tools origionally developed for linux or the "java ecosystem" on windows. But that's the way it is now adays. And Microsoft knows it too.