I will share my experience and findings as I have shared it in previous thread regarding the subject.
My brother has VSX-509 (for 10k). I have yamaha 630 (for 19k). we both use 8.3. we exhange materials. Our notes shows my yamaha sounds thinner than his pioneer. His pioneer sounds full - not bass-shy.
I shied away from Pioneer due to my experience with VSX-3800 which I think is bass-shy.
So what's going on? After so many experiments on various type of speakers - full range, contemporary, DIY, vintage, etc - and diff amps, sansui, technics, yamaha, pioneer, vintage, mono blocks - my other brother tried to find out our issues.
The pioneer of my brother sounds good because of his placement. His house has the ceiling following the roof - unlike mine, just flat throughout. His listening area has a place to have the 8.3 placed 3 ft from the corners without being a hassle for the rest of the family members, unlike mine, can only do it at most 3ft on a side but 2 ft at the back. Further discovered that my listening area is a bass hole in the middle - I have the best bass just at the entrance of the door to my listening area.
Part of the experiment is with the VSX-3800 I gave t my father since I do not want its sonics (probably because of the speakers - or its placement) - just because I espoused some unfounded basis - like that of IC versus discreet - like the LM3886 vs discreet , etc etc. We modify a speaker system to have a 10" full range (coral) with reinforcement on the HF. I have another brother who helped us correlate experiments. After this setup, I am convinced that VSX-3800 is not bass shy, and in fact I am trying to recover the amp and find a suitable speaker for it. We enjoy its lively sound - from bottom end to high frequency.
My yamaha is not bass shy, as some would have it stated just like that - a simple statement as if is is just the amp.
Bottomline - the choice of your speaker and the matching to the amp and then the room placement (room modes) greatly affect the total sound of your system.
Pioneer is bass shy to what speakers and room placement? and so Yamaha is bass shy on the same ground - and the rest of amplifiers/speakers for that matter, unless your amp has integrated tone alterations on the preamp section to make it bass heavy.
I still have the 630 which is bass shy for 8.3 at the location I choose before - so I change my speaker, change my listening position. My brother still enjoys the 509 with 8.3 in full range (large speaker) - will not give it up.
Now, we just threw some of our unfounded notions about this amp is that and that amp is that. So many variables in the art of listening - so we realized.