I used to own the ESP-950, driven from a Stax SRM-001, and the sound was smooth, detailed, and very musical.
I then got the SR007 MKI driven by the KGSS, and the detail is that much better.
The spacing, extension, and details are a few notches above.
That said, my ESP950 + SRM-001 was about $1100 - $1200 combo, the SR007 and KGSS is close to $3000.
I would say I would be perfectly content with the ESP950 if I never heard the SR007, but now there is no...