Originally Posted by
Kilian.ca 
I recently bought a Denon 3312 and the Onkyo 818 (never had either brand AVR before), been trying out the Denon first and only last night the Onkyo. I've only run XT fully on the Denon, not yet the full XT32 on the Onkyo. The Denon has passed the 30d return period.
What I've found so far, not in any particular order and bear in mind I don't use all the features and I use it mainly as a pre-amp. YMMV...
1. There are pros and cons to the GUI in each. The Denon GUI is more confusing at first as it changes dynamically, but it's easier to go to submenus by using the → on the dial. On the Onkyo you have to press ENTER. Same for going back up a level, on the Denon you can just press ← but the Onkyo you have to press RETURN.
2. The Onkyo is 10lb+ heavier than the Denon (but my Arcam is the heaviest 50lb+) but I am using mostly pre-outs so this isn't a major factor.
3. The Onkyo has FH pre-outs but not the Denon, this might be handy for me for fine adjustment to the FH volume using a stereo int. amp. The present 3 tier on the DPLIIz is just way too crude.
4. The Onkyo accepts DSD in but not the Denon, again not a major consideration but nice to have the option to compare the age-old debate for myself.
5. The Onkyo only will output 2CH PCM audio via HDMI 'TV out' whereas the Denon can output MCH PCM even dts-HD to another AVR. As I use another AVR (Arcam) this is useful and gives me a choice of which pre-amp to use and compare.
6. The Onkyo has GREAT difficulty recognising MCH PCM after using 2CH PCM source, keeps saying NO SIGNAL despite many attempts. Had to reboot the AVR itself. No such problem with Denon at all. This is possibly a problem for me as I play both 2CH and MCH music.
7. The Onkyo has THX modes not in the Denon, not particularly important for me (never tried it nor a great believer in it) but nice to have it to try.
8. The Denon has AL24 upsampling, not a big deal for me. It can't be turned off which is a bit daft. Give us the option to choose.
9. The Onkyo has more video adjustments, not particularly useful as I have a DVDO VP and Kuro plasma with isf modes. I'd prefer to have the option of using the Marvell vp to do 1080p upscaling as well. In any case the HQV should be better than the one in the Denon. None of the AVRs have the option to set frame rate (50/60) or colour space (YCbCr 422/444 vs. RGB). A dedicated VP is still better if you like tweaking.
10. So far I've not found a way to display incoming signal info on the Onkyo (audio sample rates, video resolution etc.). On the Denon I can but is rather deeply buried in the submenus. It's quite easy on the Arcam to see audio info.
11. Both AVRs' pre-amps have significantly less gain than my Arcam AVR. On it's own I normally listen at +30 to +40 but using either Denon or Onkyo as pre- I have to turn volume on the Arcam to +65. If I don't do that Audyssey won't run properly as the levels are just far too low.
12. On the quick Audyssey set-up (just one run on the MLP to find the approx. levels), the Denon gives options to show the channel levels before saving (or cancelling) but on the Onkyo you only can see the XO points. To retrieve the levels you have to save it first, then exit Audyssey and go elsewhere.
13. Height channels: before running XT the Denon sounded very strange on the height channels with very choppy sound (music source), haven't noticed this on the Onkyo. Not sure why.