I got my amps yesterday. Like a little kid, forgot how long a day I'd put in at work, and went about hooking them up. Don't need the manual, very intuitive. I disconnected my mains from the B&K amp and played some music. I don't really know how to describe the difference. I have heard people say 'sounds warmer' don't know how that really applies to mechanical, all I know is I really like the sound of my Polks, its just different somehow.
I am using the music sense switch, it doesn't lag at all. As soon as a track starts, it actually surprised me hoe quickly it responded.
I have had them running now for about 4 hours. They are cool to the touch, my B&K is very warm after a few minutes.
I have been a lurker here for a year, I am glad I finally took the step.