Pioneer and Sound Choice have the best performances and studio sound quality on a consistant basis!
I own CDG's from all manufacturers and I have listened to and sang with them all over the past 17 years. My experience goes back to the very first laser discs before CDG's were invented. I first sang karaoke in Japan in the mid 80's where they used large laser disc changers and before it hit strong in the USA. Prior to that you had to sing karaoke to cassette tapes with lyrics sheets which I did in the early days. We all have our own opinions on which manufacturers are best but mine hasn't wavered since the beginning.
Steve