Ok, played for an hour and a half tonight and decided to stretch its legs a bit. It took quality 10 at 1440x900 without flinching, 60FPS without fail, barely warmed up past room temp. I bumped it up as far as full resolution (3880x1800) quality 6. The frame rate dropped to 40-50 but it was immediate and it stayed there, I left it there for about a half hour before going back to 1440x900 quality 9. It was fairly warm when I switched back, but there was no apparent throttling (and still nowhere near as warm as the 16" MBP this replaced would get under load).
Again, I wasn't in heavily-populated areas so that needs to be taken into account, but... damn. Just... damn.