ssddx :
pc363d, game zero, pc350se are all similar and related products from sennheiser. adg1 is a similar sounding headset from audiotechnica. mmx300 is based on a dt770 model from 2005.
all but the mmx are bass light with decent soundstages and more treble/mid focused. with a good amp the mmx should have a bit more bass but you may not be looking for that.
any of them will work though the adg1 based on the ad700x will have a wider soundstage. not everyone likes the headband though (love it or hate it scenario). game zero/363d are similar but one comes with a cheapo sound card. beyer mmx300 is just overpriced normally.
the game one isnt bad either (hd598) and instead of being as treb/mid focused its more neutral.
you could also go with separate headphones and mic and possibly either a soundcard or amp. depending on prices you can sometimes get the same exact thing (ad700x + mic in the case of the adg1 for example) for lower price while sometimes while at other times the headset is similar cost.
i think the most important thing here is what sound signature you want...
bass light - advantageous to fps gaming but not very exciting sounding
neutral - jack of all trades but a bit plain and boring to some
v-shaped - very exciting sounding but not as advantageous as bass light
bassy - enjoyable for bassheads but lacking for fps gaming.
Yeah, I've seen your numerous responses recommending other headsets. But they all kinda make me doubt about what headset I should really get. Sorry, if I seem thick, but I just want to spend the money right the first time. I primarily use it for games like CS:GO, where sound and positioning are key elements. I won't be watching many movies with it and I probably use my in-ear specifik for music - or perhaps gonna buy the Bose Soundcomfort or what they were called.
So that being said, which would you say would be the better option for me specific? I know that they are sometimes based on earlier models, but how big is the change - both in price but also specifications?