I've got a set and must say they're lovely smooth. Have had an issue with the freehub block, it's an old sachs which i can't find a chain that doesn't skip on, so I've had to revert to a modern heavy basic shimano one.
I too have some of these on my fat and they're beautiful things although the bearings on mine need a replacement soonish
I too had the same chain problem with a Sachs Aris freewheel (I guess the teeth profile needs a specific chain?) - If you want to ditch the shimano one try a Sunrace version - don't be put off by the brand (it's in fact a division of Sturmey Archer) they're good value, well finished and readily available
Several bikes, one supportive lady and still trying not to buy anything else!