The ideal turntable motor doesn't exist, YET. All the technology exists, but noone has ever built one.The BLDC motor driven by a seriously accurate three phase AC signal is unquestionably the way to go. Unfortunately ALL of the currently produced BLDC's use ballrace bearings, which are great for long term service life but are far too mechanically noisy, the ideal solution is a BLDC 3 phase motor with sleeve bearings, but no such animal exists!. I've been developing a design for such a motor in conjunction with the applications engineers at Maxon, same form factor as the Permotech motor, but with zero torque ripple and ten times the torque. It's going take a while, but it's do-able.