I'm not a big fan of the styling, honestly. It looks like they just took two different vehicles, and sewed they together behind the back doors.
I do really like the FX45, though. Infinity has come a long way.
One other one that really caught my eye, and I'm ashamed to admit it...the Buick Enclave. They are brand new, so right now they are much more rare.
http://www.speedtv.com/_assets/library/img/large/92468_ben.jpg
On the QX56, I don't care about the price, or the fuel useage. What I do car about is how much of a pain in the you-know-where it would be to parallel park (you'll need a football field), or maneuver in a crowded parking lot, parking spots are so narrow for a vehicle that big (may be very difficult to get in or out if you can't open your doors far enough.)
Edmunds.com editors only gave it a 7.4/10 which makes me wonder if it's really that much better than the Nissan Pathfinder
Armada, which is the exact same vehicle, except for the face, butt and interior.