Well, I'd love to use it if the I/O would improve. At the moment I just use Cygwin instead.
Also depending on how you develop you might run into unsupported things. For example, I once tried to run IntelliJ Linux version on it through X11 Forwarding. Didn't really run perfectly.
So right now I am too afraid to develop in it because what if the real Linux acts differently? I guess you could always test it, but then why not just develop in Linux already?