I love being able to take soup to work without spilling it in my bag!  The gasket seals take a bit of "learning" to remove and replace, but once you have the hang of it, they are a cynch.

These are plastic, so you do have to use caution not to over heat - especially red sauces and other things that get very hot very fast, but they do take more heat than tupperware.

I have been using them since they first hit the store shelf and the seals are still just like the day I bought them.