Dear @daveyf : " nor a pretty sound..""
Well nothing is perfect and there are some issues with the vacuum hold down mechanism.
Some Micro Seiki TT models that came with the hold down the surface material where the LP rest is metal one and here exist a problem of resonances/vibrations not well damped but other MS models fixed that with a hold down non-metal contact LP surface and ovbiously all improved with this change. In the AT after market item happened the same and AT had both the metal and felt like contact surface.
In both kind of hold down mechanism exist other issue and is that the LP side in contact with the hold down must be perfectly cleaned as the hold down contact surface because the microscopic dust be sticked for ever if not perfectly cleaned.
The hold down it's not very good with the LP waves but because the LP is almost " sticked to the platter making that the stylus/cantilever " feels " less movements and we can listen its " integrity " in the reproduced sound.
The after market items gives too or works too as a flyweel adding its weigth.
R.