Wow it's interesting how everybody sees it differently.
My kids didn't like the Nude Food Movers - they struggled terribly to get them in and out of the wetsuit material cooler. And the hinges broke too easily for my liking.
As far as plastic lunch boxes being too small, I found the opposite. My kids have a huge plastic lunch box, far bigger then the biggest insulated ones.
My kids school has fridges, and they have actually requested no insulated lunch boxes as they are harder to stack in the fridge then square plastic ones, and apparently they are no good for the fridges in some way.
Is very much trial and error until you find what works best for you and your kids I think!