Honestly, in 2 Channel at lower listening levels I didn't notice much difference. Not until you cranked it up did you start to hear a difference. The Purifi 1ET7040SA just remains tighter and controlled all the way up. In fairness, my speakers have integrated powered subs for the very low htz, so that might be masking the lower level Bass differences. Hence this might not be a good comparison to others.
Sound stage is great on both. I would add that it wasn't until I got better main speakers that I actually started enjoying Pure direct 2 channel mode from the Denon. When I was running the B&W 704s as mains with the Denon alone, I actually preferred Stereo mode. Room correction and Audessy adjusting the curves a bit just made them sound better. With the Tritons, they sounded better without all the trickery, albeit they are a lot more expensive speakers!. So I guess it depends on the quality of your main speakers. A neutral amp isn't going to make average speakers sound that much better, unless the speakers power hungry or hard to drive (i.e. impedances dropping below 4-5 olms for a lot of the curve etc). In that case, more power is better.
With the Apollon, I guess it's more what you don't here being so clean/neutral. The Denon adds a slight warm to the music, which I actually didn't mind to much. One subtle difference I've noticed is the Purifi 1ET7040SA are very neutral/clean, so less forgiving on poor recordings. I've become a snob and can't bear listening to some tracks now if they haven't been recorded well lol
Overall I am happy with the purchase. I definitely needed extra amplification as the Denon was running out of puff with 11 channels. If I was still running a 5.1 from the Denon with the Tritons, then that would be a tougher call.
