The CVR is the buy....imho and for my purposes. There are changes to be made, perhaps....but those changes make it a better amp and more versatile than either of the others. The quality of build is identical in all three. ifmthey have had it that long and IF they made that $500 offer with no encouragement from you, you might get it for $450. Things to do....install a NFB loop with an adjustment pot. Install a bias pot in the back panel....there is already a hole in the chassis on the left side of the back of the chassis. That hole is hiding under the back panel there....put a hole through that thin black panel and ...voila....quick access biasing. I leave the reverb on both channels....I don't believe that that is a noise problem. The lack of a NFB loop is what makes the amp noisy, imho.