My problem is the lack of a keen ear, and/or an appreciation for good sound I guess cuz I tried like hell to hear the differences but rarely if ever did I hear one.
That's because when played within their limits, the only thing you should be hearing is speaker/room interactions. It's why people need to stop worrying about whether X receiver is too warm sounding vs. Y receiver and compare them in terms of functionality - does it have enough inputs for your gear, does it have pre-outs for external amplification, is the user interface intuitive and easy to use, etc.
I swear, it's like people are busy trying to pick up pennies off the ground with their cable risers, $4500 speaker wire, warm and cool receivers, etc. when there are $50 and $100 bills falling from the sky (using better speakers, setting up your room properly to accomodate them, multiple subwoofers for bass, etc).
When I bought my Denon 4311, I spent
ZERO time worrying or caring whatever sonic difference my mind may have incorrectly thought was there. All I knew was:
a.) The 4311 had preouts, rendering the internal amplification moot should I spend the money.
b.) It had Audyssey's highest non-pro level room correction to try to work out any room issues I had.
c.) It had provisions for integrating 2 subs better than most other pieces of gear. Which, would be useful if I had subwoofers.

d.) It had enough inputs for my different sources.
e.) Assuming it doesn't break down on me, it would hopefully serve my needs for quite some time in the future.
So, I wouldn't feel bad about not hearing anything. Just find a well built receiver/pre-amp that has the features you want and go enjoy your content.