Just got back from ISSE, here are my thoughts:
Disclaimer: I have a cold and running nose that might have affected my listening impressions, but my own iems still sound great to me so...
I was an owner and great fan of the MA750.
I was... Unpleasantly surprised by how thin and shrill sounding treble are on both models. The bass was not overpowering like the T10 and T20, but the mids were recessed and the trebles were just... Terrible. I have no idea why RHA tuned them that way. I tried both CL750 and CL1 from their dac amp, but no difference... It's really impossible for me to recommend anyone to get them, fan that I am of the MA750.
I didn't spend enough time with the dac amp to formulate any kind of impressions, just that there isn't anything special about it to justify its price. The treble and bass knobs work as advertised, but since all my sources tend to be flat and neutral, I prefer the knobs set to off.