mtemur and n+1, which string or belt do you use with your Verdier and original motor? I think, that if you use a very elastic string, the w/f that you measure is not because of a good motor, but because of the high mass and inertia of the platter. The elastic string will compensate any motor irregularities.
Of course after all you need a good complete system, and in this case it is fine.
But if you really want to test the quality of the motor alone (and not the whole system), you need some rigid belt or tape drive. In that case the measured w/f will be really the result (mainly) of the motor.
And another question please: how to do measure w/f?
I check w&f with iphone apps and measure it with computer software such as wfgui and AM. Unfortunately 70’s or 80’ standalone equipment is very primitive by measuring maybe less than a second. I only care about AES standard.
You are right about high mass platter’s positive effect on w&f but it’s not only because of that. Good w&f performance is a total result of high mass platter, bearing clearance, oil viscosity, relatively low power motor and more importantly magnetic levitation. Magnetic levitation zeros high mass platter’s weight. So there is no load on inverted bearing but motor still has to turn the same high mass. Both are good for better w&f performance.
Another important factor is basic power supply design. It doesn’t have an encoder to report actual platter speed and no feedback circuit to readjust it accordingly. Power supply has a regulator and sends steady DC (5V AFAIK) to motor but you have to adjust speed manually everyday you start listening. It’s not effected by line voltage changes but viscosity of oil in the bearing changes depending on the temperature so the load on motor changes too. BTW the change during 4 hours of constant use is low and negligible.
Regarding the benefits like ease of flow and great dynamics I’m happy to adjust speed everyday. It takes 30 seconds.
As a result we can not say that only the motor is responsible for good w&f performance it’s the result of whole design approach.
IMHO vinyl playback requires to be a little deep in hi-fi hobby and using La Platine Verdier requires to be even deeper, more like a diy hobbyists. It’s not a plug and play turntable.