I was very excited upon hearing that the Q CORE (the most comfortable pad out there, in my opinion) was going to be upgraded to an ultralight format that would only be slightly heavier than my EXPED UL7.
After picking up the pad I must say that it certainly is comfortable. The unique air chamber system leads to an incredibly cushioned pad (especially for back sleepers). The R Value is terrific and the pad deflates and stores terrifically small. The pad is also tougher than expected, despite the Ultralight fabric.
The downside? The pad is NOT sized correctly. The regular size is not 20"x72". It is much closer to 17.5"x70". This makes a BIG difference as you will NOT be able to rest your arms on the pad at ANY point while laying on your back. For side sleepers, some part of your body (either your knees or your butt) will be hanging off the pad.
To suffer both a size and weight penalty for this pad (despite how comfortable it is on my back) is too much for me. Unless you're a smaller person or you don't mind springing for the Large/Wide size, I would steer clear.