I think the LUXE may be what they are now calling the women's M.U.L.E. I got it on sale last summer and have been pleased (hint- REI likes to put this Camelbak on sale). The straps are narrower than the MULE my husband has, maybe the whole product is narrower but they both hold 100 oz. This one has nicer straps than his MULE but his is a couple years old. FWIW- it doesn't look like they have changed the men's straps but maybe they have. Otherwise I say storage is identical- both have a ton! Basically, they are the same product but the LUXE is cut for narrower shoulders and maybe a shorter torso. I really wish the REI site showed the vent/padded back. I am sure you can find that if you looked. This is similar to mine, just a darker brown now.