Hey guys. I got gifted a pair of MT-300's, I believe for Christmas, so I figured I'd chip in my two cents on the subject. I've got maybe 5-8 hours of on head time with these so far. Also, I'd like to state that I've yet to read anyone's review of these so far so if my thoughts are congruent with others' then maybe we're on to something.
Overall. Silly good for $5, imo. It's actually hard for me to rate this headphone at times. Easily, there are areas for improvement throughout the entire sonic presentation, but then I remind myself that these are $5... I mean, irrespective that my pair actually were given to me, if I was buying these for myself I'd basically write the expense off as "free." It's hard to critique something you got for basically free.
Detail. Pretty good. Being an orthonaut I feel it's difficult to wow me in this area, but it easily passes imo as a damn good $5 headphone. Not quite sure at what price point you could outperform these, but I'll blindly guess an average of 10x their cost. More on this later.
Bass. Reaches pretty deep. Nice bloom making a lot of music fun to listen to. I'd say it's on the verge of being one-note-ish, but I feel it's more simply a lack of texture. It sounds very realistic in attack and tonal character with a lot of percussion, imo. Electronica music tends to reveal its flaws, however. While it maintains a dynamic level of bass that's astonishingly clean for a $5 pair of buds, it lacks the tactile "blap blap" that you often get on complex bass passages in this genre. I'd take a tighter bottom end for a small sacrifice in overall output.
Midrange. Magic. Not too upfront, not too recessed, just right. No overly obvious funky coloration going on that I can tell. These guys nailed it. The only thing I can really even point my finger at is that the upper-midrange is my limiting factor on volume. I find that these buds like to be played at moderately loud volumes, but once you get past a certain threshold the upper-mids get shouty for me. Some headphones with very flat response can basically get louder until the SPL just hurts in general (read permanently damaging your hearing), but with these there's a definite peak in the response which may hinder people from pushing all the way into "fully rockin' out" mode.
Treble. Slightly recessed and slightly fuzzy. This is the reason I want to turn up the volume, I want more top end. With this in mind, however, it'd take one hell of a hot track to get shrill on you. These have yet to get sibilant on me. Speaking to the "fuzzy" remark, I feel cymbals have a certain "shhh" where I'm used it sounding like "tshhh." I feel there's a lack of resolution in this range which could be said for the entire frequency spectrum -which I guess I just did- but I feel as though it's most obvious in this region.
Build quality/aesthetics/etc. It's hard for me to judge these, I've only had them for a few days. I like the buds themselves, they feel solid, and I feel like you'd have to make a pretty big oops in order to break them. I like the included tips, they fit well, and they feel like they'll last many baths in the faucet. They do tend to slide up on the ear bud fixture upon insertion, however, which can force me to either have to push the buds in further (which can lead to an unbalance between channels sometimes) or remove and reposition the tips. I haven't had any issues with the cord so far, but it is thin and the rubber doesn't feel very strong. I sort of wince internally when I pull these guys out of my ear by the cord, I'm just imaging the strain relief giving way or something. This could be a completely unjustified remark altogether, and hopefully it is, but that's just an early observation of mine. I'm scared for that accidental snag. All that said, the cord is very soft and not microphonic very much (almost at all) which is awesome especially if you know how bad buds can be in this department. I've worn these for a few hours continuously with no discomfort. If you're not used to buds, though, I'm pretty sure these will take the normal break-in time for your ears to acclimate to IEM/canalphones. My ears were sore for a week after I got my first pair of IEM's. Some days I'd just use cans to give my ears a break, it was that bad. I don't expect these to be quite that bad, but I would expect some discomfort for newbies. Give them a chance.
Recap. Hopefully I didn't sound too negative through all that because honestly: Awesome buds for $5. I'd have 100% no problems using these as my primary portables. They really are that good, and the price tag is just icing on the cake.