Implying price paid for gear = knowledge is kinda silly really, esp when you admit you've yet to get any schooling on the subject and are obviously brand biased. I only mention Pioneer as being less flat sounding in the lower price ranges, not as an across the board superior brand. I'm not here to dispute the $600 plus units because I don't shop in that range, nor do most.
The mainstream, esp in a stressed economy is the under $600 units, and that's where Pioneer's DSPs definitely breathe more spaciousness and depth into the midrange, and that is largely, despite outsourcing, what's kept them one of the largest selling brands in that price range. Marantz units start at $400, and at that price you aren't going to get the quality of sound their higher priced units have, or much power for that matter. Their Slimline models have a mere 50 watts per channel.
I take what so called "audiophiles" say about sound coloring with a grain of salt, because what they don't get, and aren't familiar with, is how muted, muffled and constrained midrange is in most lower priced AVRs, because they never shop in that price range. Coloring or not, subtle DSP programming can considerably open up the detail and spaciousness of the midrange in lower priced AVRs, where it would otherwise sound almost non present in some respects.
The "audiophile's" answer of course is to throw money at it, often considerable amounts. Not everyone can or wants to do that depending on their budget and/or needs. I'm sure some spend far more than it's worth to get schooling on sound design only to end up just getting knowledge that serves those that buy expensive gear, while the majority go on being the mainstream and ignore them and their holy than though attitudes.