The Wheeled Underseat Carry-On With Back-up Bag has a large main compartment, front organizer compartment, zippered front pocket, mesh expansion pocket, and a full-size back-up bag that folds for compact storage.
PROS: Fits under most airplane seats, but not some aisle seats. Lots of pockets for organizing.
CONS: The handle broke after 3 trips. It was replaced by the company and on my first trip with the new bag, the handle wouldn't retract oompletely. This turned it into a bag that needed to go overhead thus defeating the reason I purchased it. I'd look at different bags in the future.