The lid is the whole story. A box that stacks without the lid locking down tight will slide off the pile the second you bump the shelf, and you will bump the shelf, always on the day you're carrying something hot or breakable. Before anything else, check the lid clicks on all four sides and not just the two ends, because that's the difference between a stack that holds for years and one that dumps itself on the floor every few months.
The cheap ones go cloudy and brittle within a year or two, especially if they ever sit anywhere that gets sun, a garage window, a shed, the top of a closet with a skylight. The plastic goes from clear to a sort of yellowed frosted glass look, and the corners get that stress whitening where they're about to crack. A good box stays clear, keeps its flex, and the hinge or clip doesn't wear loose from being opened and shut a hundred times. Looking after them is almost insultingly simple: keep them out of direct sun if you can, don't stack anything that isn't flat on top so the lids don't bow, and wipe them out before you put the next load of stuff in, because leftover damp at the bottom of a box is how you end up opening it in March to a smell you didn't know plastic could make. If a lid ever gets warped from heat, cold water and patience will mostly bring it back. Heat made it that way, and it'll relax out of it eventually.
On delivery day or in the shop, check the actual walls, not just the lid. Press the side panel in with your thumb. If it flexes a lot and feels thin, that box will bow outward once it's full and heavy and never sit flush against the one next to it. Check the corners are molded as one piece rather than glued or welded together, because that seam is the first thing to split when a box gets dropped, and boxes get dropped. And actually stack two of the same box before you buy them, not just look at them side by side on a shelf, since some ranges photograph as a matching set and sit at completely different heights once you try to line them up for real.
If you own none, start with a plain, clear, mid sized box with a lid that locks on all sides rather than snaps on loosely, and buy more than you think you need in the same range, since mismatched sizes from different lines never stack as cleanly as you want them to. Clear over solid color too, so you're not relabeling things you already labeled once.
Does this lid actually lock down, or is it just resting there looking confident?