Pros: Very comfy / Overall good sound quality
Cons: Rendition of the low-lows
To sum it up... They sound great over almost the full frequency range and with almost all music genres imo, just the very low frequencies are a bit lacking imo, and unfortunately EQ'ing doesn't help much here (it seems they are simply not capable to output em properly, perhaps because of the open design, closed ones do usually better in the low-lows). So, for everything besides very bass-heavy music (and here we have enough alternatives) this headphones are great. Since my Denon AH-D2000 died (broken driver) the DT880 became my new primary cans (tho I still prefer the sound of the Denons... dat smooth extending lows *love*).
The DT770/880/990 Pro are the most comfortable cans i tried so far, very nice!
If you are looking for a good "prime" can that doesn't cost an arm and a leg, give em a try.