Satellite and DVD, which both use MPEG-2, can have widely varied picture quality. It all depends on bitrate, and unfortunately, cutting down on bitrate to fit more in (either useless extras on DVDs or more useless subchannels on DTV) seems to be very popular these days
I put in a Sesame Street DVD for my son yesterday. That probably was the first time I've watched a DVD in a year. Wow. The picture quality was amazing. My eyes have become overly accustomed to the over-compressed DVB images on FTA and ExpressVu. It is a shame that analog channels are going to become a thing of the past. Probably the best images that I've seen on a Standard Definition TV are all analog C-Band or Ku-Band signals direct from the satellite.