You'll have to do a write up in a month or so and let us know how you liked each model. Hope you enjoy the new toy.
Jack
I'll give you a basic idea right now.
The Pioneer 918 seemed louder (keep in mind, this is just using the auto mic setup with minor manual adjustments on both receivers: ie. YPAO and MCACC).
The Yamaha seems smoother, ie, less harsh when pushed. Could be because the Yamaha may have more available power. Who knows.
I do like the the ergonomics of the new Yamaha remote, but none of the buttons glow. It's impossible to see what you are pressing if you have a darkened room. Whoever designed the remote is an idiot. It feels really cheap and light compared to the old Yamaha remote, which had the main buttons glowing in the dark.
I don't know why manufacturers don't offer a backlight button. It's not difficult to implement. My projector's remote has backlighting and it's fantastic.
The Surround Cinema modes are nice. You can actually tell the difference between "Adventure" and "Spectacle". The Scene buttons are a Godsend for me. My girlfriend can simply hit "Scene1" and see "PS3 Blu-ray" light up on the Yamaha. This makes it so much easier for others to use. It extremely convinient to have one button have all your surround presets assigned to an input.