The 4500 is a better receiver. It has the AL32 processing which the 3600 doesn't and I've been very impressed with it which I have on board a Denon SACD player.I have a dilema. I was able to snag a X3600H online for $870 shipped. I received the package yesterday. They shipped a X4500H instead. Do I keep the X4500H (2018 model) or have them send me what I ordered (X3600H 2019 model)?