It depends on what you want, and what you expect. I'm happy for the improvement of SD material on my Panasonic 55GT50 with a DVDO Duo. I can see "ringing", but the improvement in contrast, noise, picture distortions, and scaling makes it worth it. Out in remote Montana, we don't have HD local stations on Dish, just SD. The Duo makes a difference for me. I hear that HQV and Lumagen are both very good too.