After long research and even longer waiting for Schiit MJ3 here in Europe, I'm converting to Mentor. Hopefully, it's not a mistake, I still can't be sure. Both seem to be great, MJ3 might be even stronger in bass, looks like. It's just a feeling and I want to support a company like Flux.
Still trying to decide whether to leave the door open and order it with mono input or not. Most likely I will never need it, but what if I will reach that state and age that I will just feel I need to buy it... It would be cool, I never dare to do monoblocks with my speaker systems.
But maybe at that time, I'll rather want to try a different flavour of headamp rather than the same twice.