After many years I routinely try to come back to these as if they'll suddenly improve on my next listen, but unfortunately they just don't sound very good. I'm not too familiar with the 110USD range, but I am with the 25-60USD and the 250-350USD ranges and I can say that this is not a middle ground I'd ever spend money on if I were to do it again. I have a 25 dollar pair on-ear Sony's (ZX-300) I put a couple foam pads into and as a result it sounds much better than these. I have a 60 dollar Sony basshead pair (XB500) and it tops these in every way stock.

My least favorite part is the treble and bass, both in quantity and quality. The quality of the treble is abrasive and unrefined (aka there are phasing issues, whether it be the enclosure or less likely the driver). The quantity of the treble tricks you into thinking they are 'precise', but for me it just gets fatiguing extremely fast. The bass quantity is also very heavy and that level carries into the low mids a bit but not in an enjoyable way. The bass quality suffers from what the rest of the spectrum does, a lack of dynamic range and phasing issues that result in a 'loose' sound. This is a headphone I'm afraid to listen to at my normal volume because it does occasionally surprise me with some resonant interjections in the ~500 ~8k Hz regions where there really should be none.

Sound stage is almost non-existent despite there being actual outer reverb channels on the baffle. Sounds like everything is playing in half-mono. Sound wise all in all these would not be very good for professional mixing, mastering or sound design applications.

The comfort is not uniquely terrible or anything (I suffered through PSB/NAD's designs so I know a thing or two about that), but the pads feel almost on-ear as much as over ear for me and my ears are not that large. The ear 'chamber' is very very small and your ear will press against the thin foam over top the plastic baffle. The pads are not very soft. These get pretty hot while wearing them.

If noise isolation is an important factor to you, these are fully sealed and isolate very well. Not my thing to be fair, I don't like hearing my own bodily functions while these are on.

The build is a high quality plastic one, but the pleather headband material will deteriorate and flake off over time. I don't like how heavy these are, they really have a presence on my head, especially with the claustrophobic ear chambers.

If you can pick these up in decent condition for around 50 bucks they might be worth it if you have nothing better already.

I'm going to be critical of these, but don't take that as me slamming them. FOR SOUND ALONE (I have no use for the noise canceling and will not factor it into this review at all), If you can handle the ergonomics and can grab these for ~80 USD used I'd say that's a fair deal since they're definitely good sound-wise. They sound pretty similar but with key differences to the NAD VISO HP50 by Paul Barton, same author as these. In short, they're a bit louder, quite a bit warmer, have a tiny bit more ~8KHz and the treble is not as well defined.

They sound just about as 'wide' as the HP50 and the soundstage is of course impressive for closed-back headphones. I feel that they lack some of the dynamic range of the HP50. The treble sound very similar to my 50 USD Sony MDR-XB500 in that it is not very well defined and it is pretty abrasive, but it's not so bad that you're missing all the details and I would say the M4U-2 are slightly better in that regard. It's got that sort of rough texture to it that's polar opposite to what I prefer in the HP50's ultra-soft and careful treble. The bass is similar to the HP50 and very good, but a little heavy for my tastes.

For sound alone, the energy (transients sound great, close stuff sounds close), frequency response and the percieved clarity of everything make for decent monitoring headphones, but be aware that ultra-fine mixing of treble might not be very rewarding on these, and both bass and treble might get fatiguing without an EQ. For actual long-term mixing sessions though, read on...

Comfort-wise for me personally, they're bad. Headband is heavy on the top-center of my head, much like the HP50 despite their visually different designs. The reason for this on both designs is that the headband is not angled against the cans like most headphones and the cans don't rotate on the axis that would allow for this. I'm really not sure how this kind of mistake is made. Headphones with perfectly round pads (AKG's for instance) get away with it because the rotation of the cans around your ears doesn't affect anything, but the M4U-2 and HP50's cans are oblong, so you can't just rotate them like that and the headband doesn't account for it either.

In theory, to curb this you'll have to tilt the headband further forward on your head, thus rotating the oblong cans on your ears and thus altering the sound and the comfort of the pads. Unfortunately with the M4U-2 as opposed to the HP50, the headband doesn't extend very far even in its stock rotation (so, not for big heads), and that coupled with the rotation-uncompensating top band cushion this isn't as viable. The better option in my experience is to remove the headphones after about 30 minutes of listening.