Steve, audio components are quite congenial; your new Denon components won't mind a bit that they're working with an HK. About the only thing I see where the 3801 would have an advantage is the 7 channels of power, while the 520 has 5, but with pre-amps for 7. This might not be significant to you if you don't plan for 7.1. The 520 has Logic 7 processing, which many consider to be superior. So far as the power, there's no significant difference in real-world operation. In particular, all channels driven simultaneously at full power for an extended period is a condition that exists in the test lab, but not in the home. Far too much attention is sometimes paid to it. Both receivers are fine, there's no good reason for you to change.
