These bags are fantastic. Solid material and my clothes are still sealed air tight in the bags, 3 months in. The bags are large enough to store and flatten out about 4 massive down-filled winter parkas, among other things.
I should mention that the package came with some defective bags that had leaks. However, after getting in touch with their customer service, they immediately sent me brand new replacements free of charge. The customer service is fantastic and the company stands behind their product warranty. Can't ask for more than that.