I always use the MultEQ as my rears are ported speakers close to the side walls and my centre is inside the tv stand so without it there are some serious tonal balance issues and with it on everything is smooth and motion is fluid. For the last two weeks whilst my wife and kid have been away at her parents' house I've been enjoying not using DynEQ and DynVolume, but in a couple of days I'll have to re-engage them and re-callibrate. I simply cannot watch any movies at any time other than mid-day saturday without the use of DynEQ and DynVolume. A lot of people complain that it really adversely affects the sound and I agree when you only set up using the auto setup. I find though that if you have a good disc with test tones on it and an SPL meter, if you do a manual calibration with the DynEQ engaged you can dial it in much better than it dials itself in and end up with a very good sound that's only a hair less detailed than the unprocessed sound but much more enjoyable and easy to handle at lower levels.
After letting the auto-callibration do it's thing, get out your SPL meter and tones disc and then set the AVR up like this:
All speakers set to LRG
Subwoofer mode set to LFE only
Play your pink noise test tones and setup the individual speaker levels using the select button on the remote to adjust your levels on the fly. When you get done with that, note the values of every channel on paper. (the Denon only applies the "on the fly" settings to either DD/DTS, DTrueHD/DTS-HD, or PCM individually) Go into your speaker setup menu and set the levels of your channels to your noted values (this applies the settings across all formats).
Now reset your speaker sizes and whether or not your wish to send LFE + Main bass to your subwoofer.
You will now have the system set up for use with DynEQ and it should sound as rich and full as without it applied, only difference being that you won't lose bass response as you dial the volume downwards. I find that the autosetup ends up leaving you with far too much bass in the DynEQ setting and you end up needing to dial it back along with your surrounds. Once this is set up correctly it also become quite acceptable to use DynVolume especially in its least intrusive "Day" setting. This is how I often have to listen to films in the evenings and is the best compromise between audio fidelity and family harmony that I've yet to come across.
That is until I win the lottery and build myself a fully sound-proofed screening room.