Magnetic levitating turntable shelf-opinions?

As Ed says, my platform does only isolate in the vertical dimension, as the others are blocked by bearings and posts. The fact that you can't levitate in more than one dimension was derived in the previous century. The platform does act like it is suspended by four springs, however actual springs could not operate in the same region nor change parameters as rapidly as the magnets do, so they are better than other mechanical systems. In my arrangement, the turntable rests on cones and a black diamond racing shelf which are on top of the platform. Together they are a significant mass and do not tend to move. My interest is in suppessing the large transient vibrations generated by, say, someone dancing on my wood floor. It does that very well. Due to the mass of the system the vibrations are not transmitted to the table and dissipate elsewhere.

I built one for my TT after moving it to a location where floor vibrations could not be completely dampened. My major problem was keeping the magnets apart. They can easily be coaxed into flying together unexpectedly and any unfortunate appendages falling between them will suffer the consequences.

I have heard no difference between the table with and the table without the strong magnets nearby (except for the suppression of floor vibration which works admirably). The field is essentially static and strongest at the corners of the platform where the cartridge isn't, so I wouldn't expect there to be much of an effect on the signal. I am using a Grado moving iron cartridge rather than low output moving coil, so your mileage may vary.