These days that manufacturer warranty is worth considerably less. They usually don't answer the phone, they barely answer email with people that don't seem to understand many of the issues.
If your unit fails and you did not buy it NEW from a dealer - you have to look into where you can send it. Then, you spend $80 to $100 in shipping and after it gets there - they don't have the parts to fix it? I have waited 6 weeks on my repair. If 2 months pass, Denon says they may offer to replace the Denon 4500 with a replacement unit. Meanwhile, you have no receiver for months.
Is that the fun experience you want with a refurb unit? Welcome to my guided tour of the process. lol