I have an 4311, can you give me good reasons why should I have to change for a 4520?
Or best to keep it until new technology arrives?
Any difference in quality sound?
I disagree. I purchased the 4520 immediately after it was released, and I paid list price. It was a decision that I made, and I don't appreciate someone who doesn't know me calling me gullible. That type of comment adds no value to the thread discussion.
Each time the 4520 lost power, it also reverted to a prior configuration. This forced me to re-load from backup each time. I opened a case with Denon last year when I was experiencing the same problem with my 4311. Although they promised to escalate the problem to engineering, the case was closed with no answer. I called Denon back today, and reported the same problem with the 4520, and once again they will escalate to engineering. I'll report back if they provide an answer.
Followed up with Denon on this issue. They still have not received a response from Engineering.
Remember to save those configurations to your hard drive!
August, 2012. Regarding your theory that units with this manufacture date are defective, keep in mind that this issue has been observed on the 4311 model as well (I have both a 4520 and a 4311).