Running Visual Studio on OS X
You can read all about his experience and see what he likes and dislikes about it. He also goes on about one of the problems running Virtual Machines on your computer, the fact that they eat your RAM away and could leave your host OS starved for resources. He goes on and talks about his sweet spot to prevent this from happening.
Also looks like he claims Parallels doesn't need PDTweaker after all from this post.