Do the lo-fi-ish qualities of the R70x not bother you?
Well saying it's lo-fi is already implying something bad about them...
I find them a safe pair of hands. I adore the MDR-MA900 despite its slightly sloppy presentation at times. The R70x is an overall improvement. I wouldn't personally describe them as grainy at all though. To me they're pretty darn clean. They don't have the immediate clarity in the highs that the AKG K712 has (which has more texture overall in the upper regions) but I'm still not sure if it's a quantity or quality thing.
Overall I still can't decide if I like the K712 or the R70x more, but the R70x seems like the better all rounder to me. The R70x is the kind of can where I can throw on any track from any genre and still be pretty darn happy, which is not something I can always say about the K712. It also helps that I find them super comfortable, which for me is literally at least as important as the sound.
Did you ever hear the MA900?
As for the M70x I quite like it and use it around the house. It's detailed and forward without being too aggressive for me. But I really don't like the sound when I'm outside the house. The background noise forces me to turn up the volume and at that point the treble becomes too much for me.
