Whoa! Can we return to civility here? Opinions are just that -- opinions -- no need for personal insults.
On to the question. I have Magico A3's, which I drive with a Krell FPB 300 cx, a Class A amp. Have not heard the Bel Canto Ref 600's, but years ago had a Bel Canto Class D power amp but did not find the sound natural at all; it was cold and "steely." I cannot comment on current (no pun intended) Class D amps, other than to say I have never heard one that sounded natural or musical. I love the A3's and the Krell works perfectly with them -- more than enough juice and a slight touch of warmth. I suspect similar amps like Pass also would work well.
Neal