Went out and bought the Audio-Technica ATH-M50xs. They're just a bit over a hundred euros so I thought, fuck it, might as well give them a try.
First impressions are super positive. The cups are pretty small and the clamping force a bit high, but despite that they seem comfortable enough and if things start getting to be a bit much, I'll just stretch them out and buy bigger, nicer cushions for it. The Brainwavz replacements come highly recommended, apparently.
I love how they sound. The bass is fucking massive, but I don't feel like I'm losing any (well, much) detail in the mids and highs, though admittedly I'm not sure if I could even tell unless things were real dire lol. They definitely have that feeling of BEING THERE that my HD598s have and DT770 Pros lack - for some reason, the sound in the latter is sort of.. Hollow. Like there's something between the drivers and my ears. In fact, I'm enjoying these to the extent that I'm kind of wondering if my DT's are somehow defective or something.
I also tried a few games of Modern Warfare and feel like I'm having a considerably easier time locating sounds around me. With the DT770's I'd hear the footsteps, but I'd have no idea where they're coming from.
Oh, and the passive noise isolation seems pretty incredible, too. Definitely gonna be my go-to for gaming, my PC can get pretty damn loud.
But the real test will be over the next weeks and months, of course. Impossible to say right away how I'll feel about these later.