I would not put them in the same class. Be aware that Sound United owns all of these brands...
Denon, Marantz, Onkyo, Integra, and Pioneer.
At this point we haven't seen these companies merge into one, but continue to compete against each other.
Pretty much only Yamaha seems to be the one standing in competition with all of these other brands.
But, I would not call Onkyo and Pioneer, just as I wouldn't call either of them a Denon. But, I certainly would lump Denon and Marantz together for their design implementation. Yet, they are still separate in purpose.