Sukkah depot click into each other. I believe they are made of treated wood with rubber gaskets at the seams. They only need connecting pieces for stability (so they don’t flex open and disconnect) at the tops – between boards and on corners. You can build a decent size sukkah in about 10 minutes.
I’m not sure about leiters- I believe they are very similar, but require connecting pieces between panels to actually attach them. Unless that’s an old design and they have something newer. Also, they might be fiberglass and lighter than Sukkah Depot.