@lewm, Correct, the belt is a first order filter so the attenuation would be 6 dB/oct. But, by the time you get up to the vibration generated by the motor nothing gets through to the platter.
The motor platform or bracket is attached to what Sota calls the cover. The sub chassis which holds the platter and tonearm is isolated from the cover by damped springs with a resonance peak at 2-3 Hz vertical. Sota does not specify horizontal resonance which is certainly higher perhaps 5-6 Hz. The Superiority of the MinusK platform is that it's horizontal resonance is almost as low as it's vertical resonance. The problem with the MinusK is that it can be a bitch to handle a turntable on it because it is very floaty. You have to be very gentle to keep it from bouncing. The Sota on the other hand is a delight to handle. You can use the cover to brace your hand when you cue the record. You can drop the dust cover and nothing happens. In order to get the record to skip you have to hit the turntable on it's side hard enough to move the entire turntable.
The next advantage of the Sota is that it uses a magnetic thrust bearing. It is the thrust bearing that generates the most noise as it is subject by far to the highest pressure.
My real problem with direct drive turntables is the presence of a large oscillating magnetic device right under a very sensitive magnetic device. Speed wise they can be very accurate. Noise depends on the quality of the bearing. I know of no direct drive table with a magnetic thrust bearing. In the end, stable, accurate speed is stable accurate speed by whatever means. I prefer my motors as far away from the cartridge as is practical. It is an instinctive preference I admit. The requirement for a suspension is not instinctive. I can demonstrate the superiority of suspended turntables to anyone in just a few minutes without playing any music.