I was very unimpressed by the 512 in comparison to the Burmester 001 in a demo earlier this week but I'll be back next week to demo them again against a unit I know well, the X-01 Ltd, this time in a proper environment. I really like the styling of the 512, it's just one hunk of machine, clean straight lines. As to past models, I never really thought much of the performance of the 390S.