I have put one of these into an SG copy I have with humbucker pickups - It does exactly as they say. I am a bit old for thrash metal so never bother with level 5 but the others sound good to my ear. I wouldn't be tempted to try it with a piezo though as I doubt you will get beyond clean boost without getting loads of feedback.
The 9v battery lasts for ages and it is really easy to wire in place.
The price seems a good deal (in the UK it is £17 http://www.axesrus.com/axeElectronicsEffects.htm)
David Lloyd said:
... I now add a battery box - I just received 5 of these off ebay and they are great for the price $2.95 +$1.99 shipping
David, do those battery boxes have integral contacts or are they just an empty box?
Thanks ... T.