The input impedance will work very well with the dspMusik and dspNexus DSP processors with balanced outputs. They will drive 600Ohm balanced loads.
The input impedance is part of the reason the amps are quiet, as less thermal noise from the front end. Lower gain is great as well since you typically do not use it all in preamps as they are mostly attenuating not amplifying with most modern sources.
Only a few more days until they hopefully start shipping the production BOSC amps.