Apart from eating one accidentally (with no harm resulting) I have yet to use them. I keep one for treating bleeding wounds, but haven't yet gotten one. It's claimed to be possible to create a beverage from it, but I don't know why I'd want to use it for that.
I believe they're all the same, and if they're not, I don't think anyone has figured out how to differentiate them, let alone how they differ. I think the name is generated from a small set of words, and I've seen that ones with the same name don't stack.