I'm surprised how many people are taking Denon's side here. Dealers, perhaps?
I fully agree with the OP that Denon reliability and customer support is not good enough for the prices they charge for their products, and have a similar aversion to future dealings with the company. Furthermore, a 4306 isn't THAT old, and was like a $2000 box new. So to my mind one is justified in expecting perhaps a little bit deeper spare parts bins than a company might keep for a $300 box.
My opinion is colored by the service I've personally received from Denon. I've bought a fair number of Denon components. Over the last half-decade, an AVR-4306, an AVR-4308ci, an AVR-3808ci, the Feature Upgrade (Audyssey DynamicEQ, etc.) for both of the '08 models, and a pair of AH-D2000 headphones. Going back further, I even had Denon head units in every car I owned from 1994-2009 (currently have two DCT-950R's and a DCT-A100. I only stopped using the Denons because by 2009 I discovered that McIntosh HU's could take a Clarion iPod adapter. McIntosh makes the only car HU's that are more pleasing to my eyes than Denon's offerings. (Sonicallythey're all interchangeable parts. One pays a premium for looks more than anything.) I'm not apt to do so in the future.
Here's a summary of the two experiences I've had with Denon customer service over the past two years.
(1) While they were a current in-production item (which I believe they still are) my AH-D2000 headphones lost a screw. Their unipivot design isn't terribly well engineered, and the ear cup falling off because the screw falls out is a fairly well-documented occurrence.
I called them, and asked them to send me a new screw and washer (the washer is rectangular and not a standard size) for them. They wanted me to pay to ship my headphones to NJ and fix them. I pointed out that it would be cheaper and easier for everyone if they could just put a screw and washer in a small envelope and mail it to me. They also claimed that it was a rare issue, and they'd never heard of it being a problem before. (In response to which, after mine was fixed, I sent them an e-mail entitled something like "what you know (or should know) about AH-D2000 failures." with a number of links to customers commenting on the issue) Eventually, after several e-mails and calls, they did relent and just sent me the damn screw and washer. Now I'm careful with the headphones, and end up having to tighten the screws about once every 3-4 months to avoid a repeat. Now, they're great sounding headphones, and comfortable. Aside from that design flaw I love 'em.
(2) Christmas 2011, the digital audio board of my 4308 went out. It would only pass audio in Pure Direct mode, from analog inputs. Nothing over HDMI (audio-wise; video-switching worked fine) and nothing over optical or coaxial digital either. I called them, and they directed me to a local authorized repair center. Turns out it'll cost about $550-650 to fix. IF they have the parts, which they weren't sure of. Denon was unwilling to fix it gratis. OK, the box is maybe 8-9 mos out of warranty. My solution was to toss the 4308 to the curb and buy an Anthem box to replace it. I also then sold my 3808 on craigslist, because I didn't want to have anything to do with them any longer. (The 4306 I sold when I bought the 4308.)
Yes, electronics sometimes break. Even great ones. For example, two weeks ago my Oppo BDP-83 - which everyone from Lexicon and Ayre to end-users agree is a great machine
- developed a sticky loading tray. I called Oppo to inquire if they had a local authorized service center. After all, it's well out of warranty, as I purchased it when they first were released. I wasn't asking for a freebie. However, their CS person literally apologized
to me for having trouble with their product, and issued an RMA for me. I sent it to them. They e-mailed me the RMA in an e-mail that expressed "regret" my Oppo product needed service. I sent it to them. They e-mailed me again when they received it, and expressed "regret that my Oppo product required service." THREE AND A HALF HOURS LATER, I received a second message, again expressing "regret," and informing me it was fixed, with a FedEx tracking number. In the box was a detailed description of what was done, a further expression of "regret," and informed me of the repair warranty. Oh, and they issued me new original packing material, and even put the unit in a new tote-bag. (I sent it in non-original packing material, I think from a Pioneer Elite DVD player I used before the Oppo. For some reason, I lost the Oppo box, but still had the Pioneer one.) End result: whenever I'm looking for a new disk player (or other audio part), I'm going to see first if Oppo has something to fit my needs.
And IMO, companies selling four-figure AVRs and $300 headphones need to behave more like Oppo than Denon.