I've tried all three extensively and the M-100 is definitely hands-down the best for BASSHEAD. Not only does it have a really solid bass boost that does not bleed into the mids/trebles. The bass has a solid impact, extends really deep into the low sub-bass, and is very tight and accurate without being bloated/muddy.
If you think that the M-100 is too bass heavy, then I don't think you looking at it in a bassheady perspective :P lol.
For me personally, the M100 boosts the bass very nicely right up to the edge. I've played with the EQ settings a lot & any more bass boost would be too excessive for me personally. Any less bass causes the headphones to lose it's extreme fun factor. However, I have EQed down the bass for classical and other non-bassy genres, and the M100 performed admirably. However, on its default settings, the M100 absolutely rocks all kinds of electronica/trance/dupstep/house/hip hop/bass-heavy songs & legit makes you want to jump around to the beat. I actually cannot study with these headphones because they are so engaging with the bass causing me to focus more on the music rather than the books lol.
I disagree that the MDR-1Rs are bass light as the AKG K550 & the Sennheiser Momentum has less bass than the MDR-1R from my comparisons. The MDR-1R has this strong midbass emphasis that definitely colors the sound. however, I don't think that the MDR-1R have great sub-bass extension. 1Rs are super comfy, but I don't think of them as basshead or amazing bass.
My second favorite bass for closed portable headphones after the M100 was actually the AKG K550 bass as its bass seemed extremely clear, detailed, and had amazingly low sub-bass extension. Even though the bass was not boosted, it sounded pretty legit. very different from the M100, but still really cool. Listened to the Hans Zimmer soundtracks (like Dark Knight & Inception) on them for hours on end.