You guys get to tech. for simple questions. XVCD is an non standard vcd. You can set the res. where you want, the bitrate to what you want, actually you can dam near change what ever. There is no standard for it. My personal prefrence is the xvcd. I usually keep my bitrate around 1650 1700 when I have to add filters to keep the file size down. Of course I usually deal with DL vids of the web, so I probably wouldnt use XVCD if I was ripping though.
As for the guys above if everything was all equal, chickman is right, but then there are so many other things you can do to produce better quality.