I received these through a blog network I'm in, for reviewing. Haven't actually used them yet but I'm impressed by the features.
They're basically like Tupperware except they lock on the sides, which is nice since I generally bring my Tupperware meals to work. They also have a vacuum seal, so they will keep things fresher for longer. I like the "date feature" on the top too, you set it to whatever day you started using it (ie, if you start using it on the 1st of the month, you set it to 1; if the 2nd, you set it to 2; etc) so that you know how long things have been in the fridge or freezer.