Not to discredit him, but I don't think you should use 6moon's word as the final verdict. Skylab already did a great review, and for the money and all technology and features Jan has in the amp you really can't go wrong.
If you don't need true balanced, I don't see you getting a better amp than this for the price. The volume control in the Concerto has the same sonic advantages as a stepped attenuator, but you get much more flexibility, like 2x the steps vs Burson and Goldpoint, the AD797 op amps are regarded as just as good, or better than discreet designs (discreet vs IC being much like SS vs tubes), you get active balance performance, AND the option of cross-feed.
For single ended purposes, It really is awesome and I am absolutely dying to get mine .
I had Meier Swing for a few months - very good amp; that is why I paid for Concerto without hesitate. I'm just curious what Mr Ebaen will write because he will make comparison Concerto with Burson.
If J. Meier will send my Concerto tomorrow - I will receive it next Friday.