Has anyone see the recent headphonia review of the M-100...it gets utterly destroyed by this reviewer and he even goes as far as to call other reviewers liars for commending them. Please note I own the M-100s (my work cans) and M-80s (love them both) as well as D-770 Pros', Senhheiser HD500's, and few others.
I sat down with Blutarsky tonight and we listened to my M-100 together (okay, we took turns) and he agreed with me that the M-100 is a fun sounding portable headphone that's a good match with our iPhones and iPads. Detail was very acceptable, and mids were rich and life-like, while bass is a tad much but not way too much.
With some gear the bass is about 2-3 dB too much, which can be solved with a little EQ or different gear (I didn't hide that fact in my review). But that didn't keep me from really enjoying these headphones, especially with portable gear. The EF6 amp is not what the typical M-100 owner will be using to driving them - and it wasn't a good match with my very efficient Grado HF-2 either (although great with HD800, HE-500, HE-6 and LCD-2).
There are other headphones that have a similar bass-heavy flavor, like a stock Denon D5000 and Ultrasone Edition 9. No, these aren't on the same level as phones costing 2-3x as much, and not a giant killer, but I think they are well worth the $310. They also remind me of being like a closed HD650 but with a bit more bass and a little less detail, yet would appeal to HD-650 lovers who need a portable or closed headphones. They are both are relaxing and non-fatiguing, unlike my HFI-780 that became sibilant and less fun. And they don't have a "closed headphone" sound like my stock D2000 did. They are more life-like than my HD25-1 II or SRH-840 or re-cabled and dampened ATH-900, although a little less crisp sounding.