Primary advantages of netbooks are that they're relatively cheap, portable, and low power.
For development tasks (like Visual Studio) you want screen space, loads of memory, and perhaps some CPU power. Portability probably isn't important unless you develop while traveling or on clients' location.
So things netbooks are good at, are things that probably don't matter much to you. And things you'd want are exactly the things a netbook doesn't shine at. Not saying it wouldn't work, but it looks like a bad choice to me. Better spend that money on a larger screen or more RAM.