I never had a problem with 'grainy' treble with the MA900. I've seen that mentioned a few times. I can say without hesitation that, on a good recording, the sound of orchestral strings is reproduced much more accurately and closer to life than with the K702, especially the treble component of that sound. I know because I spend a considerable amount of time sat in an orchestra and amongst that sound. It's actually the very sheer speed and openness of the treble that makes these headphones exciting to me. For treble I found to be better than the HD598, HE400, K702. I'm not going by graphs, I'm going by what I hear. Many of these headphone graphs do not correlate with what one hears.
I directly A/B'd the MA900 with the above three cans with my brother, as I couldn't believe how much better, more open, fast and engaging they sounded in comparison with the price taken into account. He agreed too. It was very obvious to both of us.