Mounds - I'm certainly no expert. I've only used the ziplock bags twice now and have never used the spacebags. If something is prone to wrinkling a lot, it still may wrinkle some. But things don't wrinkle as much because they don't slide around in the suitcase. By stacking the folded clothes in the ziplock bag, they help each other stay in place. I don't take all the air out, I leave just a little air in. In my opinion, that keeps the clothes from wrinkling. When you take all the air out, the clothes get all squished together and just look like they are already getting wrinkled. I'd certainly be open to others opinions, though. I could be wrong about how I'm doing it.

Another reason to use the ziplock bags is to keep things dry. I've heard horror stories about suitcases being left out in the rain for hours or even being dropped in the ocean by mistake when the crew was transporting them to the ship.

Also, many people say that when the clothes are packed in clear ziplock bags, the airport security people like that better because they can easily see what you have and then they don't mess up all your carefully planned packing by rummaging through loose clothes in the suitcase.

Any other opinions?