(sighs) Ok, so here are my final thoughts on Roland RH-300:
After about 30 hours of burn in, the sound began to shift toward the low end of the spectrum - it became noticeably fuller and warmer, but unfortunately also lost that initial sparkle and magic and in the upper mids/low treble. That's too bad - I expected that these would keep the same sound signature but would clear up and sound more controlled with more burn in, but that did not happen. Up until 30 hours, the sound did clear up and the bass tightened, but after that the sound signature seemed to have started changing quite significantly and became not quite suitable for my tastes.
In conclusion, I would say that if you like a warm sound with emphasized upper bass/low mids and a non-fatiguing, mellow, somewhat recessed treble, then these may just be your headphones. Unfortunately, they lose to similarly priced and even cheaper headphones like Hifiman RE0 and Shure SRH840 in overall detial resolution and clarity, but do have a more realistic tonality that the Shures (but not as realistic as my Hifiman RE0). I think that they are worth the price, if you like that kind of pleasant, warm, lush sound and don't mind or even prefer sacrificing a bit of analytical detail and clarity for a more musical and natural presentation (and also very dynamic BTW). These may also benefit from a good amp.