First you unbox the thing and you find a plastic "case" (if anything is just like another box really) and the headphones are inside with a WARNING SIGN !
The warning just states High SPL for some reason and the specs are inside. Not sure why should I be so worried, the sensitivity is nothing out of this world.
I will just mention this headphones are 150 ohm which I consider a very good number because it's low enough to still be powered by a decent DAP (by decent I mean something like a Fiio X1) but high enough to work properly with a strong amplifier. The build quality is just like a DT770 with slightly lower quality headband, everything else looks as durable as the Beyers.
At first you try the headphones and they're unwearable because the stock pads probably were never meant for human ears on the first place. They ruin the sound because they crush your ears and they're don't allow the proper distance between driver and your ears for this particular headphone to sound good. Get some DT770/880/990 pads or HifiMan pads or any 10cm pads velour or pleather it doesn't really matter, just make sure the aperture and the depth are enough to fit your ears properly.
Another thing to keep in mind is the cable. I personally like this particular coiled cable, it's like long enough for a dap on your pocket, yet it will protect it from falling to the floor. However it's still a negative because it's non-removable, coiled/short should be always an option but not the stock.
Once the pads are ok everything turns to nonsense. You can confirm your new pads are working by pushing the headphones to your head, you will notice how the sound becomes garbage when they're too close, then let the pads restore the distance and enjoy. I don't know how this is possible but this headphones sound like a very flat and well balanced closed monitors on the highs and mids, but this doesn't come at the expense of lows, the bass is nowhere as anemic as the regular flat-ish headphones/speakers that start to rolloff at 70 Hz.
There's a lot of definition that doesn't come at the expense of soundstage, the since they're technically semi-open I would say they're around 6.5/10 open.
They don't really leak much sound but you can hear people talking to you and they definitively don't have the seashell/cavern resonance color of closed headphones.
I can't say much more about the sound than they're my new "reference" headphones, what I hear from them seems to be the truest to the source. They don't really shine in any category other than having a signature that doesn't really emphasize any particular frequency over the rest and having a good balance between soundstage and definition. They don't seem to have much problems with speed/decay but they're nothing amazing really, obviously you will need to spend more money to get headphones that are good in this category (because it requires more research/development).
Overall this headphones are my favorites under $100. I reckon the pads and the cable are a terrible downfall but once you get past that (they say the cable mod is very easy) this headphones are very enjoyable and useful for critical listening. If anything this headphones are my Jack of All Trades, Master of None, I could go portable, I could listen at home, I could monitor some tunes, they won't fail.
UPDATE: The pads you chose actually influence the sound and by a lot. The DT990 pads I'm using now remove some of the bass boomyness muddyness, the DT770 pads will increase it a little bit. There's more you can try with AKG pleather pads and others. So far the DT990 pads I like the best because they sound refined and the bass looses all the resonance and unwanted boomyness. You end up with bass so true you can even taste it.