I finally got the chance to try these headphones at Mike's Headfonia store in Jakarta.
Sorry for poor quality photo.
First of all, the build quality on these is absolutely amazing, I would like to think even better than the M-80. Everything feels solid, tough and well made. Build quality, I would give a 10/10
Comfort wise, I found the clamping force just right but the cup size might be a bit too small for my ears. Not as bad as the Sennheiser Momentum though, the cup on the Momentum is too small for my ears. Comfort is a 7/10
Sound wise, I find them to be a mixed bag. It's not horrible but it's a bit uneven to my ears and also very genre specific.
To start off, the star of the show is the bass, and I mean lots of great quality bass. It has lots of impact, lots of body and great quality too. It's quite tight (not as tight as orthos mind you) but it's nicely textured and makes music sound dynamic and fun but sometimes it can be sloppy and overbearing and lacks finesse too, it's more of a brute force attack kind of bass. I would rank the bass on these an 8/10.
On the treble side, I find them to be pleasing. It doesn't show any sign of roll off and it doesn't show any sign of sibilance as well. It has decent detail and is well defined but it lacks air and overall quantity. I would give it a 6/10.
Now on to the bad news, its midrange is sucked out and too withdrawn to my tastes. Vocals are too "weighted" (don't know if it makes sense), they feel like they are being held back massively. The tone is on the warm side, snare drums don't have that right bright tone but a more subdued one that makes it sound quite unnatural. It's not bad mids but it's too withdrawn and that's just disappointing. I would give the midrange a 4/10, I really think it could do better.
Soundstage wise, I didn't really bother but I found them to be small and too closed in. Well maybe because I listened to the Fostex TH600 before listening to the M-100.
I really wanted to like the M-100 as much as I liked the M-80 but that sucked out midrange really bothers me. Maybe I'm just a midrange and vocal head but I do not think these are for me. It makes a great portable can though, where an emphasized bass is needed to compensate interference from outside noise.
It really is an headphone made for DnB, Dubstep, EDM or any kind of electro music. I was wowed by it when I heard Self vs Self by Pendulum. That track showed everything that is great about the M-100 but when I put Stockholm Syndrome by Muse, I was extremely disappointed by it. I would really avoid it for rock music.