Recently I was replacing my HD650 (Massdrop edition aka HD6XX) with closed-back headphones. Briefly I'm used to work with neutral headphones and I really like sound of HD650 but I need headphones that are closed-back and wanted to try something more 'fun' since I'm not professional. For listening setup I used Behringer UMC202HD + Schiit Asgard 2. It's going be mostly subjective feelings and not technical details.
I narrowed down my options on two models: DT 700 Pro X (having had a positive experience with Bayerdynamic before) and Meze 99 Classics (recommended on some forums as 'fun' but still good sounding).
Comfort, desing
Meze 99c are exceptionally comfortable, allowing me to wear them for hours. However, the sensitivity of the metal band to touch is a minor concern, as it produces a noticeable sound with every touch. Subjectively I think they look and feel amazing. Accessories are convenient and add value to the package (I mean hard case and cable with microphone is big plus for me).
DT 700 Pro X are definitely less comfortable - noticeable heavier and more squeezy. I also experienced discomfort in my left ear due to an earring I'm wearing but that was not an issue with the HD650 or 99c.
Sound
Well, Meze 99c left me disappointed although they're good sounding headphones. I knew that they're not studio headphones but for that price I expected more. Bass lacked precision and felt muddy. It was sometimes hard for me to catch details in it. Mids and trebles were more detailed but somewhat off balance - High mids and low trebles felt too loud.
I found DT 700 Pro X sounding great and somewhat flat. Compared to HD650 they had more prominent bass and trebles but felt less 'smooth' and compared to 99c the bass was less prominent but felt clearer and more precise.
Both 99c and DT 700 Pro X have good sound stage and imaging but in my opinion HD650 is clearly superior here. Also both headphones doesn't leak and have decent isolation.
Summary
Despite the excellent sound of Meze 99c I decided to return them due to described imperfections and stick to DT 700 Pro X. The only thing that I'm not fully satisfied with is comfort of wearing.