I hear good things about Rottendog and many of my friends have Rottendog MPU's. But Jeff Kohout had a System 11 MPU for my Grand Lizard. Actually, I replaced all my boards with PinballPCB parts, except for the PinScore LED Display and speakers. It's like having a brand new pin. Service from Jeff was very good and the boards came plug and play. The MPU swap out literally took me less than 15 minutes (OK...the wife did help). This was not cheap to do, and I probably could have sent the old MPU out for repairs as the problems were minor, but when all was said and done my GL now plays like a new game right out of the box. I thought about listing the old MPU on EBAY but for now I think I'll just keep for a spare.