Purchase a receiver or what? need your advice.


Hello everyone, I will be purchasing a Sony 65" 930E  during this holiday sales season. Along with it I want to pair it up with a power source that with take advantage of the full 4k experience.

I will have a 7.1 speaker configuration consisting of Polk RTi12 fronts, Polk FXi A6 for the surrounds and rear surrounds, Polk CSi6 center, SVS PB 12 NSD subwoofer.

My source will be a Oppo 205 4K Blueray player. 

I have been looking at two AV receivers... Denon 6400H and Marantz 8012. Their specs are pretty similar. I have a Denon receiver that I use at work that must be 15 years old that I have never had a problem with,  so I kind of trust the build quality of their product.  

So should I pick one of those or should I go another way?

Thanks for your input. 
meambler
The Marantz stuff has excellent design and build quality.  Very good power supplies and Marantz is the only receiver that has a fully discrete analog output stage.  The sound will be very strong and full.  However, the Marantz is voiced on the warm side, so you will have soft and rolled off highs when compared to other receivers.  This is the Marantz voicing and some may like it.  I was able to test the latest Marantz processor in my system and it was very good, but definitely warm.
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The Denon will be a more conventional receiver "sound".  Another option to look at is the Anthem MRX720 or MRX1120 receivers.  The Anthem will probably be about the highest resolution sound quality for a receiver.  This is excellent if you want the HT movie excitement.  These Anthem receivers could come across just a little bit bright sounding at times, but they are excellent for high resolution and crystal clear movie sound.
Agree with @auxinput.  You're getting good, but still budget, speakers so I'd be a little concerned at their level of overall refinement, especially in the highs.  If you share those concerns or prefer a richer and slightly less bright sound, the Marantz is probably the way to go.  I think the Anthem MRX 720 is a better overall unit with a more neutral sound and extremely good Anthem Room Correction (ARC) processing, but again it comes down to system matching and personal tastes.

All that said, I doubt you'd be disappointed with the Denon and you'd save a good amount of money.  Personally I'd take the Yamaha RXA2080 at that price point as Yamahas have gotten very positive reviews for sound quality, have proven to be one of the most reliable AVR brands, and now incorporate AI into sound processing that could be interesting.  Best of luck in whatever you choose. 
I may have to disagree with you just a little bit, soix.  I have heard the older Polk Rti speakers and they are actually a pretty good product.  Not the highest resolution, but very well balanced and definitely not bright/harsh.  Obviously, there are much better speakers, but at this budget, they are pretty darn good.  Another to look at is Elac speakers (another great bang for the buck - and also not bright/harsh).
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But I will agree with you on Yamaha recommendation.  Of the "conventional receivers", I think the Yamaha is the most natural sounding receiver and doesn't suffer from that "bright/cheap receiver sound" that many other receivers do have.  I just didn't want to "push another recommendation", lol.  I recently implemented a Yamaha RX-A2070 with upgraded fuse and power cord.  Result was very excellent.