Well, that was civilized.
Receivers are more than their amplifier sections and the front ends (processor/pre-amps) clearly contribute to the sound quality of different receivers.
I don't think the differences between amplifiers are always obvious. For me, the ultimate test is not an A/B test, but the long term living with it test. When a set up grows on you, makes you love to listen to it, then it gets the thumbs up. When you find yourself not listening to a system as often, or if it grows on you the wrong way ... then it gets the thumbs down.