In practice the SL1200G is the most speed stable turntable in production right now.
This is not true.
What is the SL1200G's peak deviation from perfect 33-1/3rpm as actually measured at the platter - not a crystal oscillator spec, not with a test record?
What is the drive controller's feedback system? How many times per second is platter speed read and how many times per second can it be corrected?