Pros.
Built quality: like all Beyers - very sturdy. I've read on gearspace forum that for some people DT880 drivers after some time becomes faulty, I hope it won't be a case soon.
Comfort. DT880 sits on the head very tightly (it's not flabby), but I don't feel uncomfortable pressure to my head/ears, which is great. Cushions have a nice feel to it too. I've used it for hours straight without discomfort.
Sound: my first impressions was just like when I purchased my first studio monitors to replace ordinary speakers - that it sounds flat, like it supposed to be. Technically it has V shape frequency response, but FR is more to the brighter side. It's bright, but I wouldn't say I hear sibilance, as some people mentioned and I should add that I have tried to protect my hearing throughout years so I doubt that I like the DT880 sound because my hearing is damaged in some way. Tried to listen to some bass heavy tracks, bass frequencies aren't exaggerated, but it's there, you can identify notes played. Some say that it's light on mids and one could agree with a statement, because of V shape FR, but I wouldn't say as others that human voice doesn't sound like voice or something (what this even means?!). I believe that people who say that such product is on par with cheap consumer cans are simply ignorant or maybe their background is different (spent all their life listening music on bass boosted cans, are not music producers), so for someone who is looking for new cans I would advise to be careful with evaluating such radical statements as valid. Truth is somewhere in the middle. I tried to compare (A/B) with my Razen Kraken V2 cans (bad comparison, I know), but you can simply hear how disgracefully muddy the sound of cheap cans are. DT880 has very clean, detailed, intimate sound, comparable to studio monitors; you can clearly hear/catch things like bow hitting strings, instrument player moving in a chair, etc. DT880s are good at exposing issues in the mix, they don't try to embellish the sound, they stick true to listeners/producers ears. Important note is that some people say that DT880s needs to burn in to fully experience the sound of it. This might be a fact or fiction. To my ears it feels that it sounded brighter at first and it developed in the bass a bit maybe? Or that may be my ears adapting only, who knows...
Stereo image isn't super wide as you would expect from, let's say, AKG K712 Pro, but it is wide to hear instruments separately and hear how music producer placed them in panorama. But this is exactly what you expect when buying semi-open (not open) cans. I read people complaining that there is no 3D image; I simply can't agree with this, because of things mentioned above.
Cons. It's very hard to find any. Cable is coiled (not straight), which may or may not be a preference for some people (maybe not comfortable to record instruments with it?), personally I don't care too much about cable type. Coiled cable looks cool, though. If you looking for bassy cans, you should look elsewhere (at this price range maybe DT770s, ATH M50X). Cans are semi-open, which means that sound leaks to environment (can bleed/leak/spill to the recordings), but that's by design to create wider image; these cans are for mixing/mastering, so if you looking for tracking cans, there are better options (closed backs).
