Well about the brightness problem, I don\'t think there is a DVDSanta option that controls that, maybe you can alter the XviD codec settings?
As for what I use, for a fast and easy conversion I use one of WinAVI and dvdSanta, if I need more expert settings and stuff, I use TMPGEnc Plus (and not express).
Also when converting to DVD you lose quality. Of course dvdSanta has very good quality and speed, but to get it as good as possilbe you should se TMPGEnc and 2-pass encode mode.
See the guide:
http://www.dvd-guides.com/content/view/70/59/