I got a chance to see it and it is really really damn good. I'd definitely recommend it.
Trent Reznor, Grohl, & Josh Homme recording together...really:
Great interview of Dave promoting it:
Here's some of the acts who recorded there:
Fleetwood Mac (Recorded their self titled album there)
Tom Petty & the Heartbreakers
The Black Crowes
Red Hot Chili Peppers
Nine Inch Nails
Queens of the Stone Age
If you're into sound production or just bad ass documentaries with great musicians, I'd definitely recommend this.