Dear friends: IMHO I think that to know if one TT motor is better than 2-3 TT motors in a TT design is totally useless in the practice for several reasons.
Mosin and Stanwal point out that that sole factor/characteristic in a TT design can't determine its quality performance because the TT design is not only a motor factor but a whole/series of adding factors/characteristics that along a high quality implementation/execution ( like the design on almost any audio device. ) define its final quality performance.
If we see of what we have out there on the TT overall subject we can attest that each TT designer has its own aproach ( valid or not, good or bad. ) to give his " best " answer to our needs, some ones achieve the targets or are near the targets better than others.
The differences in how each TT designer " see " the " right answer " are really wide: from one motor approach to several motors, from BD approach to DD one, from acrylic build material to a blend of build material elsewhere, from massive platter approach to low mass platter one, from suspended TT approach to non-suspension at all, from DC motors to ac ones, from air bearing design to magnetic one, from almost no-plinth to heavy plinths, etc, etc.
Now, if we ask to any one of those commercial TT designers the why's of their approaches they have , part by part , answers on it: answers that go with what they believe about, what they find on their design research, what they find on " day by day " TT work ( like any customer will hear it. ) in an audio " real " system, trying to choose the " best " trade-offs, obviously what they like and of course between a price range.
This is part of our reality that we can't make " disappear " on this thread/forum.
In the same way, if we ask to the one motor TT owner if he is satisfied ( Walker, Rockport, Galibier, VPI, ) the answer will be almost yes and if we make the same question to a three motor TT owner ( TW Acustic, Clearaudio, Transrotor, brinkman, ) he will say yes too. Even if we ask to this 3 motors TT owner if he likes more than the same model one motor his answer will be: yes I prefer the three motors approach.
This, like it or not/fortunately or not, is IMHO where we live, nothing is perfect. The good news is that we ( manufacturers, audio dealers and customers ) have a lot of " land " to improve in our future and this ( between other hings ) is a reason why we love our home audio music/sound reproduction " hobby ".
Regards and enjoy the music.
Raul.