@yyzsantabarbara The Luxman 509x that you listened to is a different sound altogether than the 590AXII. If you like the Coda integrated, which outputs the first 18 watts in class A, I'm sure you will love the 590AXII which is pure class A for the first 30 watts. What I found was that you simply cannot extrapolate the sound signature of 590AXII by listening to the 509x. They're quite a bit different.
@skypunk -- I heard both the Luxman and the Simaudio integrated amps at the same dealer and my experience was just the opposite. I found the Moon to be a little too energetic for my taste. While I didn't care much for Luxman 509x, the 590AXII ticked all the right boxes for me. It just goes to show that at this price point, it's all about preferences.