Home theater gurus, help me decide between two receivers. Thanks.?

Only the Pioneer Elite will allow you to connect 9 speakers in a single room

I'm not sure how you ended up with the two choices, but these Basically you have to have an amplifier channel for each speaker you want to connect (except self-powered subwoofers). The Elite has 9 amplifiers, while the Marantz has 7. With 7 amplifiers you can have a 5.1 + separate stereo setup (The stereo pair would normally be in a second location and used as Zone 2 connected to a different input from the main 5.1 setup) OR as a 7.1 setup (Zone 2 can still be used as a low level input to a second remote amplifier). With 9 amplifiers you can set this up as a 1, 2 or 3 zone system (9.1, 7.1 +2, 5.1 + 2 stereo zones.).

However, note that there is no 9.1 music source and relatively little 7.1, so while the Elite is a great choice if you want to bi-amp speakers in a 7.1 setup or REALLY want to have ultimate flexibility it isn't necessary for most users.

Most manufacturers make a "flagship" AVR with similar flexibility (e.g. Denon AVR-A100, Onkyo TX-NR3008, Yamaha RX-Z9) and at that level choice really comes down to price/styling and features.

I have two Pioneer Elite AVRs and have had no problems.

I would choose the Pioneer Elite. Go online to Home Theater Magazine and read the review on the receiver. I have used Pioneer Elite receivers for well over 35 years and never had any problems. Keep in mind that there are no 9.1 audio software in the market available at all. Even the 7.1 audio are very limited and only available on certain blu ray disc movies. Yamaha was the first manufacturer who designed the Digital Sound Processor, to make your room sound like a Church, Jazz club etc. in the 1085. This provided you a 7.1 set up. My current Onkyo is also a 9.2 system with the front high speakers and 2 subwoofer. Hope this will help you out.

I like the Elite but only because I own a Pioneer receiver and can vouch for them.