I've installed it tonight on my AT&T Lumia 920. Of course, I did it because I was impatient and didn't mind wiping my phone. I don't recommend it for most folks, especially since we're confirmed to get it tomorrow.
Anyway, I've already set my Wi-Fi to always on, customized my send text message "call reject" options, and played with the camera a bit... definitely very nice improvements, so I'm sure everyone will be pleased... unless you still want 40MP, in which case, really... want in one hand, and crap in the other, then come back next year for the Lumia 920 follow-up.