I installed it earlier and it seems to be running OK.
For some reason, both IE9 and IE10 didn't play nice with the new (and quite hideous) Yahoo Mail, so I'm hoping that's not a problem with 11. Every so often I'd get pissed off enough with it to roll back to IE8.
There's one thing I can't find which is a bit of a pain - in IE8,9 & 10, I could hit F12 to bring up the Developer Tools which allowed me to occasionally change the Browser Mode back to IE7.