While helping out Anima with vp, I decided I would see what's the difference between all those recording choices in the options screen.
And yes, I do suck at pvping.
320 x 240, avi format
For Naver Blog
For Daum TVPot
For Youtube - Normal Quality
For Youtube - High Quality
Professional Ultra HD Mjpeg Format
To be honest, I cant tell the difference for a lot of these, but if you want the best quality, go for Mjpeg or the professional whatever.
Don't use 320 x 240. Youtube ones aren't all that great either.