I got money for Christmas for a new backpack, I definitely want one of these two packs. My sleeping bag is a WM alpinlite, tent is a Contrail and pad is Neoair so things are pretty light. I just don't want to buy the Circuit and wish I had bought a bigger pack, or buy the Catalyst and it be too big. I would like to here from some of the Ula owners of what you like and dislike about both. I have been using an Osprey Atmos 50 it has been a good pack but for winter hiking it can be a little stretched.