I have a XS Scuba bag set: giant roller bag, mesh bag for dive boats, mask bag, regulator bag, and a dry bag for dive log. So far, I LOVE the set. Very good quality, and fits all my cold water diving stuff w/o a problem (since that was my biggest problem with fitting gear. Cold water gear is so much bulkier and bigger!).
Oh, and the only thing that wouldn't go in the "checked bag" would be my regulator bag. That I would carry on.