Most TV episode DVD's are already poor quailty and are packed in real tight. The use of any transcoder is not going to do a good job in condense them to 50% to fit to a dvdr.
The use of a quality encoder like CCE, TMPGenc or Procder can get very acceptable results however. I tend to convert each episode separately, rip the menu off the dvd then re-auther them all back to a working DVDR. A long process compared to using Shrink, DVD2One, etc but the result are worth it.
A new kid on the block, check out DVD ReBuilder. A One click dvd to dvdr using CCE for the encoding. Its still beta but working on many/most dvd's problem free including TV Eps dvd's. I just did Futurama Seasion 1 with supurb results using it. Get it from Doom9 forum http://forum.doom9.org/showthread.php?s=&threadid=73051