I've owned three Sota's over the years and if you're gonna do it, get a Star. The vacuum hold down is definitely worth the extra few bucks.
I've also owned the SME V and SME IV.Vi, one each mounted on different Sota Stars and one on a Nottingham Mentor. Sonically, I liked the IV.Vi better than the V but if you're spending enough money for either of the SME's, go with a Tri-Planar instead.
With both SME's, I was always bothered by tracing error; Graham's too. They're a bit plump from the lower midrange on down though certainly warm and forgiving. They lack overall transparency and don't resolve recordings nearly as well as the Tri-Planar.
SME's leave much to be desired when it comes to set-up and adjustments, especially considering their retail price. VTA is a pain in the ass, not precisely repeatable and not to be done on the fly. Azimuth, forget it, not available.
Tri-Planar on the other hand is sonically much more transparent and resolving and I no longer hear tracing distortion. VTA can be done on the fly, VTF is so much more precise and easier to set and dialing in azimuth is a piece of cake.
Plenty has been written on SME vs Tri-Planar and most of what I've read confirms what I'm saying. Of course there are those who will recommend a Graham Phantom but you'll spend quite a bit more, even used, and not get better than the Tri-Planar(different maybe). Then there's the Basis Vector, a good arm sonically but we're back to a pain in the ass to set up and tweek. I know, one of my good bud's has one and he can keep it.
Happy hunting!