Looked at the Osprey Ozone and Contrail, Patagonia MLC Wheelie and Eagle Creek Load Warrior. All 22" size. Unfortunately they didn't have the Ozone Shuttle in stock.

Ozone - definitely less volume than advertised. Didn't like one pole design (can't stack) and thought some internal space was wasted (fabric covering pole stretched to create a tent with trapped space underneath). Great warranty and appeared well made. That said I'm under no illusion that this could survive repeated checking with baggage handlers.

Contrail - Also felt smaller than advertised. Two pole design nice in comparison to Ozone, and stronger fabric. The opening was annoying - considerably narrower than width of bag (molded foam sides to front of bag got in the way and zippers hard to open because of lip). Because of the narrow opening, will be harder to get things in and out without making a mess of the contents.

MLC - Liked the Design and the internal organization a lot, a bit heavy and definitely not deep enough. I didn't have a ruler but I think depth was considerably less than allowable MLC sizing.

Load Warrior - warranty not as good (lifetime against defects only). More standard/efficient shape (block shaped and opening was entire front of bag). Felt bigger than others because volume was block shape, not aerodynamic shape of Osprey packs. Not crazy about the colors, but looks to be well designed. Interiors and pockets well thought out. Only a bit heavier than the other bags.

Of the four, I'm leaning towards the Load Warrior. Osprey's packs seemed less functional (and lower volume than claimed) given focus on aerodynamic styling. Reminds me of the spiel on One Bag about the efficiency of cubical shaped bags (vs. more stylish but less efficient curved bags). Seems like Osprey missed that lesson.