I think both these receivers are great, and both likely have features you won't use. But then, a bargain model Yamaha from BB likely has features you won't use. There is a relatively small difference in the price of these 2 AVRs and a lower end AVR... several hundred dollars.
What you get is more power, probably meaning you won't need to ever think about a separate amp, (unless you catch the bug). It also means features and system upgrades you may consider in the future, even though they don't interest you now, are available w/o replacing your AVR.
You say you have a 5.1 system, but don't mention a subwoofer. I suppose you have one. If you ever discover the benefit of 2 subs, a lesser AVR will make balancing them more difficult. Maybe one day you decide to put speakers in another room, or on your porch, and could use a Zone 2. Ditto.
If $500 is not a critical amount to you, I would say go ahead and get either of these 2 AVRs. If/when you become serious, look at speakers & subs.