they're highly regarded to being a waste of your money.
Surprised to read that- many of the EZ guys throw these in their orders as a good value and to bring down the cost of the of the main purchase/shipping down.

I've had really good ones - but - (and its a huge one) you never know what you have and can't get order more. Even if it or a version of it made it to production, you don't have a name.