[audiopadawan]

m50 and hd598 are like night and day, I'd figure out which one suits your needs the most and go from there...

 

[AbsolutZeroGI]

I was actually close to the same boat you're in. I went with a Fidelio X2 over my pair of 558s. They're right, it sounds pretty good, although I ultimately ended up returning them and going for the HD650 anyway.

The Fidelio X2 are over 100 grams heavier than the 5xx series. Hell they're 100 grams heavier than the 6xx series. Over a long listening session, that extra weight can become cumbersome. The comfort is far superior, but the weight kind of evens it out. At the end of the day, for me personally, the added comfort of the Fidelio X2 was canceled out by the weight, but I also wear headphones for 8 hours a day, dunno how long your game sessions are. The 5xx headphones disappear from your head, they're that light. The 6xx series do too once the clamp settles down a bit. At the end of the day, you're not upgrading the comfort really. One's less comfortable, but much lighter while the other is more comfortable, but much heavier.

Sound wise, the Fidelio X2 is really good for gaming. However, the sound signature is not in any way laid back. It's like a party all the time. The 5xx series has that quality of virtually never being fatiguing almost no matter what. The X2 isn't like that at all. That's entirely up to personal preference, though.

The X2 has a 3.5mm jack as its cable replacement, though, and that makes it practically tailor made for the mod mic.

For gaming, I've heard the SHP9500 is a good option also. It's like the Fidelio X2's cheaper, but lighter and less aggressive younger sibling.

Or just go with a V-Moda and get more comfortable pads. Or keep the M50x and get more comfortable pads lol.

Just throwing some extra options out there