I had both the momentums and the mdr 1rs, to me the momentums were better, far better, another league actually. The mdr 1r to me were very beautifull and and confortablr (although my ears touched the drivers a bit). To me in terms of sound the mdr 1rs only beat the momentums on soundstage besides that the momentums sound clearner better bass, much more clear and just a tiny bit warm and beauyifull, to me they are the perfect complement to something like the hd25. To me the mdr 1rs just sounded muffled, specially the voice. I hate muffled sound.... Singers to me sounded like they were burried. The bas on the momentums also goes lower and is much fuller than on the 1rs. Imagine the bass on the 1rs like someting close to the bass on the hd500 series from sennheiser maybe a bit more but not much).
I loved the momentums.... Unfortunatelly i sold both, on the 1r i just miss the design (they also had some built flaws), on the momentums i miss everything..... Except the confort and thats why i sold them. Best pair i had so far and unfortunatelly i haf tio sell them because the pads were too small and haf that on\over ear fit and after about 5 minutes not only it hurts as it distracts me form enjoying my music, if you have small ears momentum.