the SP-10 Mk3 likely has a platter heavier than 20 pounds, maybe 30, the NVS has a 40 pound platter, the Rockport Sirius III has a 55 pound platter.
as far as Ralph’s points;
absolutely my direct drives did rock in my room exceedingly well.
in order of performance----SP-10 Mk2 < Mk3 < NVS < Rockport.
I am specifically referring to large scale rock, meant to be played a warp 9. direct drive separates parts of the soundstage more effectively than idler or belts, scales larger, and has more slam. direct drives relative weak points......sexiness and tonal density.....are less significant with large scale rock.
all air bearings are not created equal. painting with a broad brush is just not informed. there are general characteristics I do agree. but exceptions too.
same thing with platter pads. every platter is a different case, and different tt weights matter too. no broad brush there either.