I haven't heard the Concept personally, but the few people I know with one say it pinches way above it's weight.
1oldguy,
You're not limited to an MM cartridge per se. You can also use a high output MC. My B60's MM stage has no problems with my HOMC Dynavector 10x5. It takes a few degrees more of a turn on thevolume knob, but not much more than my old MM, which was 5mV if I'm not mistaken.