water/methynol injection?

For all of you out there with a supercharged setup or know someone who runs one, is a water/methynol injection system worth the money? I keep going back and forth trying to decide whether or not to run one. I would like to get as much input or thoughts about these systems as possible. I really don't want to spend $400-$600 on something if its not worth it. Thanks in advance.

Kevin