OMG! I have a collection of the smallest size that I treasure! I use them for batch cooking taco meat, black beans, and rice for Mexican dinners. I also use one for DH's sandwich every day. I use Dave's Killer Bread, and the sandwich fits perfectly, even with plenty of lettuce. Best of all, if you open the container with the lid side down, you have a built-in plate.
I recently had a lightbulb moment and started using them for carrots, celery and cherry tomatoes (all together) so now I use zero plastic bags in DH's lunch box for the win!
They're also great for hiking and in the RV.
The original contents of the containers aren't so great, but I buy the low sodium varieties when they're deeply discounted, and the containers last for many times longer than the contents do. I figure an occasional processed meat sandwich isn't going to kill him.
Oh, be careful removing them from the freezer. If you drop a frozen one, it's likely to split or shatter. #askmehowiknow.