Pros: Mids, bass, clarity, soundstage, comfort
Cons: Treble (Sibilant)
This review was initially a bit different - I edited it after having owned them for over a month when I decided to sell them. Read on why.
I used them with an Audioengine D1 DAC/amp, and listen to a wide variety of metal, rock, punk, pop and electronic music.
So the pros and cons are exactly as stated above. Comfort is good, I do feel the headband putting a slight pressure on my head after 2+ hours of use, but nothing to worry about. The velour pads are extremely comfy and ears do not get warm.
Bass is really great in my opinion. You'd have to be a really serious basshead to think these lack it. I listen to some dubstep and Dn'B, sounds very good on these. Same goes for the mids, it simply sounds good.
As it turns out the treble which is very strong can be too much for some people, me being included to that group. The problem I have with them is that 9 out of 10 songs with vocals become extremely sibilant to my ears on a bit higher volumes. I had to turn down the volume quite a bit to be able to listen to bands like Paramore, where Haley Williams vocals get very piercing and painful to listen to. Some say that it's a recordings fault for being sibilant, but it cannot be purely the recording when pretty much all music with vocals is like this.
Now I should point out though that this is extremely individual, I'm sensitive to treble, others are not, and if you're not sensitive to it, then the DT990 might be exactly what you're looking for in a fun headphone. So while this mini-review might look more like a rant, it's not meant to be that, my overall rating is still 4/5 stars because it definitely is a good headphone, it's just not for everyone.