Pre nerfed One-eyed mask was very difficult to counter in a gun fight. The tracking was longer overall, the overshields were faster and regened your health with it, required you being shot by the person to see where they were, and increased your damage towards the highlighted person. Ever since the nerf, it now allows tracking but with less time, still gives health regen after the mark person is killed without shields now, took away the damage advantage (people were getting two tapped with certain weapons like AoS with momentum mori). I may have forgotten something because its been so long since its rework. As for Fortracer, you can track enemies if you aim at the player, lasts five seconds, and gives a small damage buff. The buff shouldn't be enough to be game changing. Yes it has wall hacks, but you have to aim at the person for some time in pvp to tag them. My conclusion is both helments are fair. Yes, one has wall hacks, and I don't remember how one eyed mask tracks anymore, but has tracking non the less. Foetracers wont be getting a rework anytime soon cause there are better exotics to use in pvp for the hunter class like stompies, wormhusk, frosties, shards, gwimsin vest, and more. OEM dominated the pvp playing field for a full year. Edit: would like to note the overshield could allow you to tank one or two shots from something like a handcannon. Every shot counts in the crucible