Here's the "other side" that argument, Bee:
When it comes time to replace that receiver, you'll have to shell out the bucks for another flagship receiver in order to equal the quality of the 4520's amp section.
On the other hand, you can pair an outboard amp with a receiver that has a less robust power section, yet a comparable feature set (X4000), for about half the price. All in all, the X4000 + XPA-5 combo cost me about the same as a 4520 would have.
You're right, it takes more cables and more space, but an amp can last for decades, while a receiver will likely be technologically obsolete in 5-7 years (if not sooner). So, when it comes time for the next receiver upgrade, I won't have to spring for a flagship receiver, because I don't have to worry about amp power. I'm free to choose a lower-priced alternative that has the feature-set I want. In this way, I believe that having the outboard amp provides some flexibility that will allow for a less costly long-term upgrade path.
Just my $0.02. Not trying to criticize your choice, Bee. I'm sure you'll be very happy with your 4520. Just trying to show the other side of the argument. When I was planning my upgrade from my 3808CI, I went with the X4000 + XPA-5 combo, for the reasons noted above. Just thought I would point that out for anyone else struggling with the same decision.
The added flexibility can also be beneficial for those of us who don't live in the US, as we often don't have access to the best selection or the best prices on gear.
Of course, while I was typing that novel, Brian made the same point, but far more succinctly!
Edited my post again to spare Bee's feelings, which I apparently damaged by saying there was a "flaw" in his argument. I guess those of us incapable of "independent thought" must be oh, so careful in our choice of words.
Gear: Speakers (Paradigm Reference Studio Series): 40 v4 (front L/R), CC-690 v4 (centre), 20 v4 (surround L/R). PSA XS30 (subwoofer).
Denon AVR-X4000, Emotiva XPA-5, Samsung PN64F8500 (64" plasma), DarbeeVision Darblet DVP5000, PS4, PS3, Sony BDP-S6200,
Apple TV (3rd gen.), Harmony One, Sennheiser RS180