Mine wasn't showing a new firmware available either until yesterday when I decided to do the network reset because the Denon wasn't showing a MAC address and I couldn't connect to it from my PC and as soon as it powered on after doing the network reset (and to my dismay it also reset and lost all settings just like the microprocessor reset does - so let this be a warning to save/write down any settings if you decide to do the network reset and be prepared to rerun Audyssey) - BAM got the new firmware available message and downloaded and installed it. Trying to operate the Denon through a web browser is very slow like it keeps wanting to time out from page to page - I'd rather just use the on screen menu which is much faster.
I currently have mixed emotions on the Denon 3311 - sure seems no where near as rock solid stable as my RX-663 Yamaha was, but then again, the 663 isn't as sophisticated either. But Audyssey beats the YPAO in the 663 hands down for newer movies! Normally I like a brighter sound, but with the Audyssey curve you can just listen to reference levels and have absolutely no listening fatigue all the way through a two hour action movie and the bass integration is also noticeable superior to the 663's YPAO (the new Yamaha's could be comparable but don't have personal experience to comment - it's also not really fair to compare room corrections since the 663 and 3311 is two different price ranges and eras but is helpful to those thinking about upgrading...) Love the Audyssey curve for new movie soundtracks (like say, Avatar), but hate it for 2-channel music and opt to just use manual eq for music listening and older movies (Point Break for example).
What puts the seal on the deal for me is that I got almost what I paid out of the 663 selling it and got 35% off the Denon so this was a good upgrade for the price out of pocket and I love the GUI and features over the 663 and don't think I could drop back anyway. Hell, I would step up to the 4311 if there was one in stock near me and could get a similar discount. You guys wouldn't believe in a million years what store I got 35% off....everyone on this forum would have a heart attack, lol. But now that I said it like that, I bet everyone could guess the store on the first try.
I still have a week to return the 3311 if I choose to and still have the new Yamaha Aventage series on the back of my mind (more specifically the A2000) and also stepping up to the Denon 4311 (since I'm loving my first Audyssey experience with new movies - maybe the 4311's higher amount of filters might make it even noticeably better) plus I like the idea of the pre-amp mode in the 4311 since I use a dedicated amp. But with 35% off, the 3311 is definitely going to be nearly impossible to beat for the price...