In reply to:
are the receivers being blind tested in the same price range?
No they are often radically different price ranges. Comparing a Radio Shack receiver to a Krell is perfectly OK. Even picking such diverse products, nobody has yet reliably identified any audible difference in blind tests.
That said, there are perfectly legitimate reason for picking a certain amp or receiver. It may have specific features you want. The aesthetic design could be more pleasing. The power rating could be better. The menu system, owner's manual, or technical support could be better.
Some amp/receiver features could be very important. Degree and type of bass management, DSP modes, type of stereo-to-surround synthesis (PLII, Logic 7), connectivity to player (e.g. Denon Dlink) could be major issues.
Regarding Axiom speakers sounding "bright", that's totally different from amplifiers. Axiom speakers can be reliably identified from other speakers in blind tests. Whether you call them bright, accurate, etc. is a subjective term. What not debatable is they (and most other speakers) audibly differ from each other.
Under the same test conditions people cannot identify specific amplifiers.
