i found the 598 better than the 6xx for positional gaming, otherwise 6xx is better in general for everything else imo
Went over to my buddys place to try out his 6xx from massdrop with magni3/modi2 schiit stax. I wasn't impressed for csgo/pubg, couldn't really pinpoint the accurate distance of sounds i hear compared to my 598/sbz.
I recently purchased x7, just gotta pick it up on Monday or Tuesday at post office when i got time and i can give you a better opinion of it.
I think ad700 headphones were the gg for fps gaming, but shitty for everything else