To the top, necro thread!
Mostly HD650 here, with some L700 and SR-007A. The HD650 is basically ideal, comfortable, smooth sound, no physical or ear fatigue whatsoever, and detailed enough where you don't have to crank it up, yet not so detailed that it reveals all audio problems in-game. The Stax stuff is better in some ways, especially the 007A with its crazy resolution, but crazy resolution in most games just makes you hear the audio problems. So the electrostats get used on things that have high-quality sound samples and good sound engines (i.e. Fallout 4) while the HD650 is used on everything else. No problems with the HD650 playing competitively, positioning is good enough. I don't feel like the Stax phones really give me anything extra in that regard, but they don't hurt either.