We have used these PYREX glass storage containers and we are pleased. Their glass is quite thick so there is little fear of breakage. Glass is the most practical and sanitary way to store food. Quite unlike plastic, it is not porous, nor does it retain food odours. The containers are easy cleaning. The plastic covers fit fairly snugly. We plan not to utilise the plastic covers when microwaving, and wash only by hand in warm water. We have found doing so will extend the useful life of plastic. The containers nestle into eachother to save shelf space. We heartily recommend.