"A $500 Technics SL1200 mkII will keep speed as accurately as a belt drive turntable costing thousands of dollars."
Maybe it will be more accurate than many turntables out there, but it isn't the end all answer to proper speed control. The reason is because it creates a sort of analog jitter in the process of maintaining the desired speed. So, if you think about it, it isn't accurate at all because both detail and dynamics suffer. A better solution is to generate perfectly tailored power to a superior motor. That can be done a variety of ways with any drive system, but you don't really fix power after the fact. A correct fix is made before it is created.
Maybe it will be more accurate than many turntables out there, but it isn't the end all answer to proper speed control. The reason is because it creates a sort of analog jitter in the process of maintaining the desired speed. So, if you think about it, it isn't accurate at all because both detail and dynamics suffer. A better solution is to generate perfectly tailored power to a superior motor. That can be done a variety of ways with any drive system, but you don't really fix power after the fact. A correct fix is made before it is created.