The 990 Pro is A LOT more comfortable than the 880 Pro.
 
If anyone is on the fence between the 990 and 880 because of the midrange, don't even bother.  The very marginal forwardness is not worth the additional cost, let alone comfort.
 
I found that the DT990 Pro looks better as well (though more plastic).
 
Both need a tube amp for sure, solid state is way too harsh (completely agree)
 
A steal for $150, I wish I had never sold them.  Ended up getting the 880 Pro, and can hardly justify the $60 difference (nor the loss I made selling the 990 Pro.)

Really good headphone and I find the review pretty accurate, well done. Looking for a good tube amp. Hopefully I could get my hands on the new Schiit Vali.

Thank you for the compliment. I wouldn't recommend the Valhalla the most with the DT990 Pro. Schiit amps run bright of neutral, so they would make the DT990 a little too glarey or treble heavy. I recommend the Maverick Audio Tube Magic A1 since it is a good deal, has great synergy with Beyers, and since it is a hybrid amp it will drive Hifiman planers like the HE400 or HE500 fairly well. 

Have you ever tried the Aune T1 with the 990? Thinking about the a1 but not sure if it will be worth it.

I have not, but the A1 is definitely worth it.

I mean to add with the aune. The amp section on the t1 is pretty clean, powers the headphones well, but the A1 looks like an attractive option. As hot as the T1 gets on normal operation I
m surprised it functions properly.
 
 
I wish I got the A1 and a seperate DAC, waiting for the T1 to breakdown lol.

Ah I see. I recommend the A1. Of course it isn't something like the Woo Audio WA3, 6 or 7 Fireflies, but it is a very good amp for the money, and the Maverick Audio D1 or D2 should be a good match with it.

@Yazen: How well does the Aune T1 perform? I've just got the DT990 and was looking around to buy some tube dac/amp..

It performs really well.  The Amp isn't WOW, but its a top performer in its price range of $200.  The stock tube doesn't match too well, check out the Aune T1 thread for recommendations.  I bought a couple of voskhods from Ukraine, and they sound a lot nicer to me.
 
Can't recommend the Aune T1 enough for $135!  I don't even think about upgrading..
 
My gripe with the device is the heat, it gets pretty hot!  Makes me worry about the lifespan..

ok thanks. will check some reviews around for some nice tubes (y)