After my brief impressions today (at Tokyo Headphone show) I would rank in this order of preference to my ears..
MS-AK100. Clear, clarity, lush mids, beautiful, slight emphasis on vocals.
RWAK100. Smooth, clear, more apparent highs than MF mod, subtle V signature.
AK120. Clear, no body, no real bass.
*check my sig!
That is exactly how I heard the AK120 right out of the box........