I speak from experience: get the good, hardshell case. The gig bag is nothing but a dust cover. I dropped my concertina, in its gig bag, and although it only went about 2 feet to the sidewalk it was enough to cause problems. It was "only" an inexpensive Rochelle, but at the time it was my only concertina. For my new, expensive concertina, I got the Pelican case recommended by the maker and fitted for my instrument.