I tried to render after settings all video clips with the "reduce interlace flicker" and the disable resample, as some people suggested at the avp.stacktrace.com:
http://avp.stackexchange.com/questions/3744/sony-vegas-10-video-made-from-s...
I also just tried to get the good looking mp4 local file and converting it using formatfactory, but after uploading to youtube the result is still really bad:
Does the videos from that channel all look bad to you guys too? Any suggestion how to improve it?