I've used these headphones for 3 years now, for producing, mixing & mastering and live streaming performance, and it's a really great headphone. The sub frequency accuracy is the best on this headphone, no other comes close. I have an yamaha HS8 with sub as main monitors, and this DT 770-250ohm, gives me the full subwoofer sound that I need to hear. I also have the Beyerdynamic DT-990 open model, but the sub woofer is not as full bloom. The DT-770 closed model better represents the bassreflex port on a subwoofer to make better mix decisions. It's very useful to hear clearly, the difference between an sub suitable for cinema, and sub tweaking for different music styles. And my sub tweaking mix/masters with this DT-770 have always translated well to real subwoofers, car woofers & club subs. The open model DT-990 has an wider soundstage (it sounds like there's an added stereo width, compared to the DT-770, if I compare it A-B. I recommend the closed one for accurate mixing/mastering of the low end, keeping in mind that stereo width isn't as wide due to the closed design, but stereowidth can always be added in the mix/master stage & can be checked on the multi correlation meters. But the sub sound advantage of the DT-770, cannot be attained on the DT-990 no matter what you put on the mix/master busses. For me it's DT-770 over the DT-990 on any day.
Comfort is also great, many hours, minimum fatigue. Might have to get used to the weight, clamp pressure, and curly cable weight & handling. But in a weeks time it will be second nature. My longest session wearing it was 22 hours. I have used it for nearly 3 years now, almost every day 7 days a week, 3 to 12hrs a day.
The foam pads/cushions are still good, good isolation even after all this time. Isolation for vocal booth/livestreaming/podcast is also great on these. I think about 80% of youtube/twitch streamers use the DT-770. It's very popular.
So yeah the Pro's: Mix/master translates well, great subwoofer clarity to make confident mix/master decisions on for the low end. Music mixed on these translates well to other systems. Also great for critical listening, referencing music & sound design. Accuracy & translation is great on these, but note the stereowidth, bit narrow sound width due to the closed design.
There's only one Con, the curly cable, if you sit stationary in your mix position you're fine. But if you move a lot to access different gear, any head movement more than 30cm, will reposition the cable & it's weight strain. Do that all day, & you'll get tired & annoyed by that cable. So sit still haha and try to have the cable rest on something like your desktop/table when mixing/mastering. Letting the cable hang full weight on the headphone will cause fatigue during long sessions, but is inevitable in the vocal booth where one usually stands upright.
In conclusion, I love this headphone for everything. Mixing/mastering [closed design isolates well, won't hear street noises & children playing, I can always focus on my mix/master]; monitoring instruments, sound design, critical listening, watching movies, and playing games. Also great for enjoying ASMR, or voice/video-calls, just make sure you have an good headphone preamp to drive the 250ohm to get enough gain/volume.
I use the RME Babyface Pro Fs, more than enough gain. But on my samsung phone max volume is about 70%-80% of what I would prefer as ideal. It's okay, not bad, but I'd recommend an headphone preamp if you want to drive the 250ohm version just from phone.
I'm married to these headphones, always reliable & true sound, never deceives me haha Cheers