RoDillaWhile these are great headphones for music, I wouldn't recommend them for FPS. For that application, you want a wider sound stage and more comfort for longer sessions.
Grado does a lot of things right, but it's very hard to pull off a great soundstage presentation with drivers the size of theirs. Additionally, the K240 was optimized for very long use sessions where the SR80 is usually comfortable for a couple hours at a time. Obviously YMMV (my head is really big so take the comfort point with a grain of salt).
RoDillaI have used these (SR80i) in FPS like BF4, COD, etc and have zero problems locating other players (I even prefer these over my turtle beach px5 surround sound headphones). There may be better headphones out there for gaming, but I use these for all around use and love them.
WillI've been using my Grado sr80i's for gaming for a while. I must say, they do a good job, but as you mentioned, they are not designed for long sessions and the hard parts of my ears hurt after very long sessions.
MilkyxjI can't yet speak to the quality of the SR80 in any of its iterations, but I use my SR60s for games like Counter-Strike: Global Offensive, and they work nicely. Granted, CSGO's positional audio isn't the best in the business, but my Grados have been my friend and ally through many victories.
Of course, YMMV. My head's not big enough to stretch out the band, and i keep the cans all the way down the slider, so there's not enough pressure placed on my ears to cause discomfort until I've been wearing them for 3 or 4 hours.