Hello

I'm very soon going to upgrade my receiver ( OnkyoTX-DS474) .I'm trying to do as much of my own research as possible, sales peeps want to sell me what they want to get rid of , and I don't trust them. I just learned form this forum that their is no real 7.1 or THX is nothing special. So their are areas that I am ignorant about, I'm looking for something for less than $800 for a room about 22ftx18ft. This is what I have come up with:

Onkyo TX-NR801 vs Yamaha RX-V1500

I don't know if its a matter of flipping a coin or if their a real difference ( aside the MP3 and YPAO).
Also considering, since I might be wasting money for nothing for my needs

Onkyo TX-SR702 vs Yamaha HTR 5790 or RX-V1400

Does anybody have any info or expirienced I should know before making a purchase?
Thanks
KS