I have a friend who owns Klipschorn speakers and uses Quicksilver amps. He recently tried both the Endler and EVS Attenuators. He kept the EVS. He said it wasn't even close.
That's interesting. Mad Dog and I actually never had the chance to compare the latest EVS Ultimate "nude" attenuators with Endler head-to-head b/c I had to take my EVS back from Mad Dog before he got the Endlers in. Mad Dog only has the older EVS, which is not as good as new version (we did compare these 2).
The EVS meets all MY needs, and I have hard time telling whether it's in the signal path or not, which is good enough for me.
There are advantages to transformer-based volume control, especially if the system is not optimized for passive use, i.e. impedance mismatch, long interconnects, etc.
But having owned both, I prefer EVS to transformer, IF the system is optimized for passives: high-efficiency speakers, short interconnects (or no interconnects in case of EVS), low output impedance from source with large voltage output, high imput impedance of amps.