@holmz , all of the arms mentioned above have quiet bearings unless they have been damaged. The real issue with bearings is play. The tonearm has to hold the cartridge rigidly allowing only two degrees of freedom. This is why unipivot arms are not recommended by many of us. The Graham arm mentioned above is a stabilized (by magnets) unipivot arm and has a great reputation. My problem with it is price. I do not think it represents a reasonable value. The same is true of the Basis arms which are not really unipivots either. They are bipivots or unipivots stabilized by a secondary bearing. They do not IMHO represent a reasonable value as there are many arms of equivalent (maybe even better) performance at a much lower price.
The tonearms I personally like best on the Sota are the SME V, the Kuzma 4 Point 9 and the Schroder CB. The Kuzma has one issue and that is the tonearm cable exits about the tonearm board and interferes with the dust cover. The other arms have cables that exit below the tonearm board resulting in a cleaner installation. I personally chose the Schroder CB for my Cosmos and could not be happier. This year at AXPONA Sota will be demonstrating with the Schroder CB. Peter Ledermann is totally invested in Schroder tonearms for what it is worth. He demonstrates with a Schroder Reference.