This is a fantastic little lunchbox. I had been looking for something without any plastic which also had multiple compartments, and after looking at some other options I decided to go with this one. I'm glad I did.
The design is impeccable. The lid can be flipped upside down and used as a base for the upper level, leaving no mess on the tabletop. The top level is designed in such a way that, when set in the overturned lid, it doesn't actually touch the inside of the lid, so if either the inside of the lid or the bottom of the upper section is dirty, the other one won't get messy. This isn't hugely important, but it does make the whole process of having multiple compartments very easy to work with. All of the space in this box is highly usable.
The build quality is difficult to describe. On the one hand, my model looks obviously warped when looked at from particular angles, and when pieces are put together, they fit snugly, if not flushly. However, everything does indeed fit together as tightly as needed (it also helps to get away from the expectation of the kind of tight-fitting seal that only plastic lids can create), although I find that the clasps snap a little tighter if I put the top part on one way instead of another. The metal is smartly chosen: a little thinner in the main sections and thicker in the lids, which would otherwise be easier to bend. As it is, the lids are quite sturdy, and the larger pieces don't seem likely to deform any time soon. I was also extremely pleased to note two details: 1) There are no seams where food could get stuck (the corners are just a little rounded on the insides), and 2) there are no sharp edges. The edges, in fact, are just a little thicker than the walls--this adds a bit more stability and prevents any possibility of injury. You will find only stainless steel throughout the entire construction: even the little rollers on the clasps are steel!
As to the size: it ended up being both smaller than I expected and larger than I need; since the entire volume can be filled with (non-liquid) food, it's possible to pack quite a bit. Unless you buy smaller-sized bread, you'd be hard-pressed to cram a sandwich into this thing. However, I have found it's given me a good excuse to get away from the sandwich and explore other horizons. Leftovers are great in this lunchbox--food can simply be spooned into the compartments, and if more divisions are needed, lettuce and kale are wonderful as edible barriers. Of course, the steel construction precludes the use of a microwave, so don't expect a hot lunch.
I have also been delighted to find that this box is very, very easy to clean. The polished surface can be blinding in bright light and does show a lot of fingerprints, but I also think it causes the food not to stick so easily; I have had no difficulty hand-washing this lunchbox even after leaving it open on the counter overnight.