I do play at 1080p, actually. I decided to go into a custom game to test this a bit. My results:
Everything maxed out (incl anti-aliasing, vertical sync, character inking) at 3200x1800: 10-20 FSP
Everything maxed out (incl anti-aliasing, vertical sync, character inking) at 1080p: 20-30 FPS
Everything maxed out (incl anti-aliasing, vertical sync, character inking) at lowest resolution possible: 25-35 FPS
Slider set to highest WITHOUT anti-aliasing, vertical sync, etc at 3200x1800: 30-40 FPS
Slider set to highest WITHOUT anti-aliasing, vertical sync, etc at 1080p: 45-55 FPS
Slider set to highest WITHOUT anti-aliasing etc at lowest possible resolution: 60-80 FPS
Over all, I was surprised at how small the difference is between 1080p and the lowest resolution; I was also surprised that the game was playable on highest slider (without the extra stability junk) at 1080p. I started trying to test the mediums, but the game glitched out from me changing resolutions too much.