I sent dd to school w/ one, it was pretty fun making her bento lunch. We did a sushi sandwich (sandwich rolled and cut in sushi shape), a small salad and a banana palm tree (sliced banana for the trunk and sliced kiwi for the leaves. She loved it, even took in a set of chop sticks....lol.
Ds can't manipulate it though :( That's a little disappointing). He just turned 6, I'm sure a typical 6 yr old could manipulated, but ds has some fine motor issues (nothing serious, they are just a good deal weaker than the avg child his age). I'm going to try and work w/ him over the weekend but it looks like I may have to find an easier to open box for him. I really don't want to send him in w/ something he can't manipulate himself. He is only is 1st grade so there are aids to help, but I know he wont ask for help if he needs it. He is....ummm....extremely shy especially w/ adults he is unfamiliar w/ (and school has only been in session for 4 days, so most of the staff is still very new to him).
These are the ones I got, overall they are nice. Ds can't flip the latches or separate the sections. The lids are a pretty tight fit so take a little bit of muscle to manipulate. So, I guess it's back to the drawing board. It took me almost a month to settle on these ones (mostly b/c these things are kinda pricey, not these particular ones just the stainless steel bento boxes in general).