Okay, so these aren't the most environmentally friendly product, though I suppose an argument can be made that you'll save the water that would normally be spent on cleaning the crock pot bowl. They have, however, vastly simplified the clean-up that comes after using the slow cooker and that's what I was after. I was a little worried that I might find melted plastic in my food but after dozens of uses (not the same one, of course!) this has never been an issue.
What has been an issue is leakage. Sometimes they don't leak at all. Sometimes they leak a little. And once, they leaked a lot. I'm not sure if they sometimes get rips in them or what happens, but I definitely have had them leak. I'm probably 50-50 on that count. Usually, if they do leak it's just a little and clean-up is still pretty darn easy, just a rinse and wipe. I do that much anyway, even if they don't appear to have leaked.