Got the upscale issue sorted,
Making a direct compare to the Yamaha,
1. Yamaha RX683 runs cooler, pioneer has noticeably more heat.
2. The version of MCACC on the pioneer from my observations is superior to the ypao on the Yamaha,
3. In 2 channel stereo the Yamaha sounds better on the higher end but the pioneer seems to win on the low end.
4. Surround sound now I’m comparing 5.1.2 vs 7.1.4 so not exactly fair, but when it comes to bouncing sounds around the pioneer is the clear winner, the 3D audio from the pioneer makes the hair raise on your neck.
5 configuration Yamaha seems to have more options in the UI and it’s system seems a little better, But on the other hand the pioneers is more user friendly and lets you adjust the the EQ on the speakers which my Yamaha did not.
6. Looks the pioneer just looks better then the Yamaha in every way.
Conclusions,
I am happy with the purchase especially at $549 free shipping and no taxes,
I was wanting a denon H4500 reciver and couldn’t find it for the price point I was looking even at used, best I ever found was at AA refurbished for $899 and a crappy 1 year warranty,
Although not the denon for $549 and a 3 year warranty from a major manufacturer I don’t think you can beat the Pioneer LX503 when looking for a 7.2.4 atmos system on a budget.