So far, I've tested the Beyer's with the Analytic pads only; these produce a more neutral/open sound rather than the classic "Beyer" sound which tends to have more pronounced bass.
They are absolutely terrific at bringing out every detail in all of my music thus far. I'm hearing little sounds that my K7XX (which are known for being very good at sound stage) never picked up. I listen to mostly metal, and my issue with the K7XX was the complete absence of bass; the DT1990s are not overwhelmingly bass-y, but they certainly excel at giving you clear, clean sound at the low-end. I had them cranked up to a pretty high volume and I could hear every single movement in Judas Priest - Painkiller. It's pretty incredible how detailed these cans are while retaining clarity even at hearing damage volume levels.
I played some Hell Let Loose, and they do great for that too. I'm not really noticing much difference in gaming, and I suppose I didn't really expect to. I'm going to try the more "bass" centric earpads that come with the cans and see how that changes the sound.
My AE-5 is also having no issue driving these cans at all. Very impressed overall.
The company I ordered them through (on Amazon), however, I'm not super happy with. I paid full list price ($599.99) and received the box without a factory seal on it. The box looked like it had been opened before. The headphones do look absolutely brand new; I went crazy looking for even the SLIGHTEST mark, finger oil stain, or blemish so I could return them. The headphones come with a case, and inside the accessories/cables. The cables were wrapped in factory plastic, and the earpads were brand new (and have that fresh "smell" to them). I'm still writing an email to the companies sales department to ask them "WTF?" but overall I'm pleased with the cans.
I'm thinking about grabbing a new mic, though. I'm getting tired of my Antlion ModMic, which is also 6-7 years old, and having to put that sticky piece on my $600 headphones. The cans are gorgeous and now they're ugly