Let me add my 2 cents on the P300...I've had mine a year and couldn't part with it. It's worth mentioning that the P300 has a RF coax in/out connection on the back (which isn't even mentioned in the owner's manual) that apparently is some kind of isolation device. I route my cable TV through the P300 using those connections, and it completely eliminated my hum problem. If you decide to buy used, make sure you're getting the multiwave option...it makes a significant improvement.