Loading performance is related to your hard drive. As per compiling, debugging, and other developing tasks, this is more related to your CPU/RAM resources. Unless you need your VM to start lightning fast (usually restricted by the OS anyway) a regular 7200 RPM drive should be plenty fine.'
Now, if you plan on developing around a database (we're talking tables with 100,000+ records), THEN you might have some considerations as the speed of hard drive.