After getting two Salsa Air cases for my daughters, as Xmas presents, I’m going to stay with my four year old Salsa (reviewed below).

Reasons: (1) The Salsa air, while lighter, has two zippable membranes that secure items in each of the halves – unfortunately this means that bulky items (for example my camera) can not easily fit in the case.  (2) 4 wheels vs 2. 4 wheels are great for wheeling down aircraft aisles and queues.  Unfortunately they cause your back to roll away on a hill, and are not so good when dragging a case down the rough sidewalks in Manhattan.