I stuffed wet beach towels in the big one and nothing leaked out, which honestly surprised me for a plastic tote. The gasket actually seals tight and the two sizes nest together nicely on my garage shelf.
The stacking grooves are the standout feature for me — I've got three of these in the garage and they lock together so solidly that nothing shifts even when I'm digging through the top one. The 44QT and 26.5QT combo covers pretty much every storage need I have without taking over the shelf space.
The gasket actually keeps moisture out — I stored some old paperbacks in the big one through a damp basement winter and they came out bone dry. Stacking them is easy too, the lid grooves lock together so nothing slides around.