I like the bungee cord on the back of the AK for compressing it if I'm not carrying a lot of gear and want it to be snug, and for putting a shell or wet clothes. I also like the front trekking poles on the UD but you are right. I have no brand affiliation or loyalty as I am just making the transition to using a vest, so I will definitely try all three to see what fits well. you are referring to the S-lab correct? That just seems like most of the 12L capacity is just in the mesh on the back. Am I seeing this right? Just checking. Thanks for your suggestions.