They do seem to be pretty durable, however they are not dishwasher or microwave safe. They are a more ridgid plastic, so might not survive a fall from counter to concrete without cracking, but would totally survive the typical banging around that plastic dishes get from kids and such.
Never tried it outside WWHOP. We got a refill from a cart around the corner from the Leaky Cauldron. Afterwards, we rinsed it out and put it in our backpack.