I've owned my VK-500 w/batpak for over a year. The power switches have been left on for the entire time and I have had no problems with the unit. It loves a good pair of upgraded power cords, I'm currently using Black Mambas which give the amp the ability to produce excellent bass and a very quiet background. I power ML Quest Z's with the VK and am very pleased with the combination. Even though the BAT is solid state, it renders a somewhat tubelike presentation and is very neutral sounding. I would gladly purchase one again...
