I love my LUXE! DH was adamant I needed a bigger one and I fought him on it for quite sometime but finally bought one when REI had them on sale. I find it fits my somewhat narrow shoulders great and is pretty comfortable, I don't even know it is there. I think the air flow really works compared to my old Siren (circa 2004 model) with no air flow pillows.

To me it looks like the LUXE will hold everything the MULE can but I am not sure. DH carries everything but the kitchen sink in his MULE but I haven't tried to put much in my LUXE.