I bought this because I was not satisfied with the 5x optical zoom on my G11 after comparing some wildlife pictures it took with some my daughter took with a P&S with a 12x optical zoom. While I didn't get (and didn't expect) the zoom she has, I found that the teleconverter definately makes a difference. It extends the built-in zoom from 140mm (35 mm equivalent) to 196mm. No superzoom and less than ideal for wildlife, but better. The difference is not so noticeable when taking pictures, but it seems to give greater sharpness and allows you to crop (thereby enlarge) the image significantly without too much much loss of image quality. All in all it performs as expected and I am satisfied with the results. One minor irritation is that you need to set the menu for the teleconverter if you use it with IS. Not a big deal and I have added the teleconverter setting to "my menu" for quick access, but one more thing to remember when setting up your shots. Also, you will need a slightly bigger camera bag to hold the teleconverter and extension tube.
Bottom Line Yes, I would recommend this to a friend