Heidrun,
A friend of mine has the 309 tonearm with upgraded bearings. This is a very nice tonearm. I have heard it with a Lyra Titan i, Transfiguration Orpheus L and Dynavector XX-2 cartridge. I cannot say how it compares with other arms playing these or any other cartridges except with respect to one aspect of performance with one cartridge--the Orpheus L. We mounted the same Orpheus L in three different arms on different tables. The one thing we could actually "measure" is that the Orpheus L tracked a little better in the SME 309 than it did in a Graham Phantom ii arm and a Basis Vector 3 arm (using an old Shure test record with increasing levels of modulation).