I have had my DT 1990's for a week now and I am quite happy.
The biggest difference is without a doubt the build quality. So pretty and solid. They sound a lot like my old DT 990's but with the balanced pads the bass is better and deeper, which goes very well with EDM. They retain the amazing detail, imaging and airy sound that the DT 990 does so well, and just adds a bit to it. Also the vocals (mids) are more noticeable. If I should find a fault I was expecting a bit more soundstage.
I have not tried the analytical pads but why would I when I love the bass of the balanced pads.
I will be clear here. I sold my first pair. I regret it a little bit. It did some bits great (really really great) but other sound features/signature were not up to the task I want them for.
After a good thought I did something I never do: I bought a second new pair, just few weeks after the first one (sn 15XXX versus sn 21XXX, £500 versus £385) . Only one hour listening, same tracks, some new bits, same set up, volume level, sound pressure, playback systems, etc.
I wrote to the online shop afterwards and they accepted my unit back and I asked for a full refund.
The second unit (now with a big discounted price everywhere from official retailers) didn't sound the same as the first at all.
The first unit has a sparkle and magic similar to that sparkle that a K501 had in the mids, forward, clear, engaging, magical. Everything else at that moment had problems, for me. It was an amazing experience, intense, dramatic, lovely. Soundstage, frequency damping/openness, and, mostly, dynamic range, was not really working. Like, at all, but it is only for me. And they were shouty but crystal clear.
The second unit, surprisingly, has soundstage, no rattle/rumble in lows, all the dynamic range I wish the first unit should have got, same great built quality, dense built, heavy sense of a well built unit.
But the sound... It was plain, grey, boring as hell, midrange/voices were several dB quieter than the first unit, no sparkle, not shouty this time of course, no magic, no drama, violin tone and timbre the same as... K712/DT770/HD650. Treble without traces of sibilance (remember I used the same tracks and lady voice as before) but this treble got muddy/busy in complex passages. Not in your face sound anymore.
All in all it was exactly as a slightly improved 770/880/990. Exactly as one. Same sound signature in general, in resolution, goals, same traits, balance in general (I mean, the balance as in what you extract as meaningful from the music, they work the same way as older models, only with a bit better sound specs but not really better music quality
per se). It is difficult to put into words what I want to say: I was trapped in a loop. It wasn't an upgrade, it wasn't a sidegrade. It was more of the same thing.
I was upset, I was tired -really tired this time-, I was surprised. The unit wasn't faulty at all. It doesn't feel as unfocused, unmatched drivers (at the end I did several test tracks to check this issue, and phase as well). But a different
tune. Both units were bought from official retailers, full price, the real thing.
At the moment, and for the time being, I won't trust them at all, even if I try a pair in a shop and they sound wonderful. I don't like/want in my life this level of inconsistency or, even worse, changes as great as those in different batches (or components inside, damping, tune, etc). I already have to give back to a shop months ago an HD650 because it sounded a lot less capable, slightly different for the worse, than a unit from a friend that was bought in 2012. But at least in this case several years passed!