I'm using this currently - I swapped from a holdall because easier to carry a backpack. It's a little larger than the prescribed dimensions but goes under a seat without problems when in the low capacity configuration, and doesn't take much space in an overhead if that's needed for the higher capacity. It has an overwhelming number of compartments though and I'm forever losing things in places I've forgotten how to get to. I can easily do a week with this.



I guess those of us who travel light also are less prone to worrying about where their own bags will fit, which may be why I'm not very exercised about this.