Great, didn't know it was out. You might want SDI at some point.
The 502 affords SDI. The 501 is HDMI only. The 502 promises cross conversion in the future. Pretty sure that's the only difference.
If you use copyrighted music in any film without sync & master rights, the rights holder to both will have claim. Let's say you get 1M views and are entitled to YouTube partner earnings around $2K - you could lose it all.
Wait for the SmallHD 502, a month or so... HDMI # SDI with 3d LUT
I would spend about half of your budget on the camera and half on a good lens. Used 5D with a good L-Series lens. The glass is so important!
SmallHD 502! Around $1,000