Lock and Lock are better than rubbermaid to me because lock and lock only has one flap per side. Th rubber maid ones I saw had 2 on the long sides.
Mine seem to stack fine, but I dont really stack much.
HANG ON!!!!!!!! I do have 3 stacked! Coco, drinking cocolate and sugar. They've never fallen over in a seaway.
Mind you sometimes I forget to put them away