I have used the calpak once so far and plan in using it for a trip to Europe. I like it except the zipper on the carry-on part does not go all the way around, so it is hard to keep it open. The back pack zips on and off easily. Similarly, the zipper on the backpack is short, going around only half the way making access more difficult. The whole unit is slightly smaller than expected with room being taken to accommodate for straps and handles. I like the padded small handles and the wheels are big and sturdy.