The issues seem to be
  • if you remember the Beatles from back in the day, you were listening to the mono mixes (Radio Caroline was mono, and BBC Radio 1 was -- according to Wikipedia but I can hardly believe it -- mono until 1988) or to mono records;
  • the mono and stereo mixes are sometimes different, including allegedly on Tomorrow Never Knows, and a suitably completomanic Beatles fan would want both;
  • it's further alleged that the Beatles themselves were more involved with the mono mixing process than the stereo mixing process, so the mono ones are in some sense more "authentic".
IMNSHO you want the stereo ones.

Peter