the marantz sound...mid-fi avrs...vs Denon....

If you want audiophile from a Denon receiver, go with the models with the second digit '8' as they are geared to audiophile tastes.
I have a Denon 4806 I like pretty much, Used with a Furman powerfactor conditioner the sound is very good.
As for marntz, I have not auditioned one, but audio oriented stores say they are good too.

I find the Marantz to be more open than Denon which always sound kind of closed in to me in my system. I have owned several from both lines at several price points and I always prefer the Marantz sound FWIW.

I've read many responses from people who site many similarities between Denon and Marantz. Like most things audio these may have been subjective remarks and subject to personal preference.
Other brands that I consider higher end mid-fi that you might want to audition are Integra by Onkyo, Pioneer Elite, and Arcam. Regardless, most solid state linear AVR's use a shared transformer to power multiple amplifiers. Using speaker systems that provide an efficient more stable load could be key to the presentation your looking for.
The Pioneer uses considerably more efficient switching amplifiers and proprietary room correction software. I found the Pioneer to be a huge sonic improvement over my Integra.

I had a Marantz THX certified AVR (forget the number, bought new in late 2000) before it fried the motherboard a bit out of warranty. There were no replacement parts available and seeing as I'd had the Marantz DVD player die shortly before receiver did, I was done w/Marantz.

I replaced it with a Rotel (1056) AVR and could not be happier. The Rotel lacks some of the features that the Marantz had, but I feel that the Rotel has a slightly warmer sound to it (which was what I wanted).

Speakers are B&W LCR6 R, L, and C up front and B&W in-ceiling surrounds. I have two velodyne SPL-10s taking care of the low stuff.