I rolled these in a Steelhead and preferred the sound of old Telefunkens to the Siemens b/c they were more 3d though the Siemens were probably more linear. It may depend on the circuit and the overall voicing of the system. At the time I was buying them they weren't hard to find as true NOS. Today, have no idea.
I went through bags of 'em in my old ARC SP10mk ii mainly b/c the phono section was extremely microphonic. I could never get that preamp to play quietly although it was a jewel in their line at the time and went back and forth to ARC many times for factory mods.