I love this brand of storage containers. They're super strong, can go straight from the freezer to the microwave, and clean up great in the dishwasher. I bought the set to test out all the different sizes. I found the small round to be the most useful (for freezing single-servings) as well as the mid-sized round one. The lids on the square containers didn't fit that great. The small one was ok, but I really had to struggle with the lid of the bigger one.