I had the SME v standard size on a SME 20/2 TT. I now have a Kuzma XL4 TT, initially with a ref Stogi 313arm (12") . I compared the kuzma set up with the SME using a Benz LP ebony in both. The Kuzma was superior.
I know this is the shorter sme arm but I found even tracking on a test record was better with the Kuzma. I dont know about the 12" but the standard smeV has no azimuth adjustment. I have found this can make some difference.
I now have added a second arm, 4pt, to the TT. This improves on the ref 313, dynamics, bass, image, are all a step up from the already excellent ref313.
IMO and others, the Benz LPs is not much different from the original LP and although I liked the Benz, owning 2, I found it a bit over romantic. I have replaced the LP with an airtight PC3 in one arm and Shelter Harmony in the 4pt. Both these carts out shine the Benz in all areas.