Cogging!

bimasta, I've never owned or even heard a FR MC201 cartridge, or any other FR cartridge, for that matter.  Does that answer your question, which I have forgotten?  (Sorry for not having come forward sooner.)

The Denon DP80 does have a 3-phase AC synchronous motor, or so I was told when mine was in for restoration.  Probably its an iron core type but built and driven to minimize cogging. Bill Thalmann thought its motor and servo control mechanism were advanced over the contemporary Technics systems. Denon published graphs to document its smooth running in their advertising literature.  (Imagine a modern company doing the same; well I guess one or two have done.)  I don't know much about the M-S DQX-1000, except based on my reading at Vintage Knob, it is an updated version of the DDX-1000, distinguished from the latter by its use of quartz-referenced speed control.

And a coreless motor helps most of all.

Cogging is a bad thing in any turntable motor, regardless of how it drives the platter.  With belt-drive, it could be even more annoying and noticeable than with DD.  But the fact is that in most any modern turntable of reputable design, motor cogging should not be an issue, even if it's happening. 

bimasta, If you hear no issues with the turntables you own, then how do you know the motor is guilty of cogging?  Is it merely because they are iron core motors?

Think of an iron core motor with only two poles as a model for the phenomenon