I've had my SFCD-1 for three years. I have upgraded the tubes to Amperex 7308s and use a Shunyata Cobra for the power cord. With these two upgrades, this unit reproduces music better than a ton of other CD players out there. I hooked up a Wadia 850 to my system earlier this year and yes, the 850 is a leg up on the SF but for the difference in price, I kept my CD-1. Sonic Frontiers offers an upgrade for this unit. I have not upgraded mine yet but will do so in the near future. They are well worth their "used" asking price.