I also recently got the Keeley Moon which is an op amp muff with some mods. I didn't notice how right away, but the filter knob seems to leave the bass intact as you turn up the treble. When the filter was less than noon, it sounds amazingly similar to my White Elk, but above that it starts to show the difference. The Moon also has a 3 way mids toggle. So, it might be my current winner.