I've never used a stroller bag with my 2 kids, and frankly, could probably not handle having one more item to haul around the airport with me! The gate attendants usually ask to see the stroller before they gatecheck it, anyway. I would definitely recommend a CAR SEAT bag over a stroller bag if you are bringing a convertible carseat on board with you. We have used ours to stow jackets inside when it's up in the overhead bin.