Received my 2310ci on Thursday, first Denon ever. Read about half of this thread and all of Batpig's info. Very helpful. Setup was pretty straightforward (I'm pretty good at reading manuals and such and understanding what's going on).
A couple of notes:
It replaces an Outlaw 1070 receiver which doesn't have HDMI, so it is my first HDMI repeater personal experience. It has more power than the Outlaw, but I feel when really cranked waaay up (louder than I would ever normally have it) the Outlaw feels a little less 'strained' although the difference is extremely subtle. In normal listening ranges the two are pretty much similar, until Audyssey is applied.
This is also my first experience with Audyssey. In testing it out I find that the Audyssey does a great job on the EQ/DynEQ/DynVolume stuff. I did find that if I flip between it being on and off that I lose a bit of my imaging (depth/width) with it on. However I'm currently leaving it on as thus far it seems the better frequency response is a bigger overall difference than the loss in soundstage. The sound stage isn't totally lost, just diminished a bit.
I did run across a wacky HDMI handshake issue, and luckily figured it out the first day. I have a Samsung TV (LN40A750), a DirecTV HR21, and an Oppo BDP-83. When first set up the DirecTV was fine, but the Oppo had white snow. I swapped out the HDMI cable between the Oppo and the Denon and it didn't change anything. Swapping out the cable between the Denon and the TV fixed it. Seems a bit odd since the snow only appeared on one of the devices, but HDMI/HDCP is weird, so I went with it.
I also had a weird handshaking issue with my DirecTV for a while. I set it up so that the Denon would use the Anchor Bay to output 1080p, and set the aspect to 'Normal.' I did this so that 480i/p channels would be in 4:3 and 720p/1080i channels would be 16:9, with everything being processed by the ABT chip. About 1/2 the time I would go to an SD channel, it would display as 'Full' rather than 'Normal' even though the settings on the Denon were always 'Normal.' When the display was incorrect (full rather than normal) attempting to display the Menu on the Denon would bring up a garbled image, like the ABT had crashed or had a corrupted buffer or some such. Luckily a microprocessor reset fixed that, and now all my SD channels are in 4:3, and all my HD are in 16:9, and no garbled menus.
I wanted to share that story in case other DirecTV owners have similar experiences.
Interestingly my unit, which I got from 6ave, only has the January firmware update, the two newer updates are not already included. Since I've recently run the setup 3 times, and had to completely do my setup twice (due to the microprocessor reset), and currently have no issues I'm going to hold off updating.
Overall I'm very happy thus far. I've never really been impressed with Denon when I've heard them in shops, but I've had some weird behavior from my Outlaw (they are known to be glitchy in some circumstances), and the ABT in the 23xx series and up caught my eye. I was finally pushed over the line by the nice discounts on last year's models, especially since I have no interest in 3D compatibility, which seems to be the major new offering in the 11 models.
I also wanted to mention that I have a Wii connected via component, and it works flawlessly. I'm trying it out with DTS Neo surround on a lark, and like it so far.