I was loan a Onkyo TX-SR706 amp to compare with (my RX-V663)
Here is the result
Onkyo TX-SR706 (against the RX-V663)
Pro
3 HDMI port in
Cool blue lights for the volume dial
Tells u what sound format is on (eg DTS, DTS Master, etc) Audio, using the light panel (big lettering)
Audyssey auto set up allows for up to 8 placement (eg to optimise listening position for 8 seatings)
The mid channel shines
Con
Very confusing speaker port (Multi colored?????)
Very weak LFE (even after increasing the volume of the subwoofer)
Doesn't tell you how many channels is the source material (eg 5.1, 6.1 or 7.1)
Surround sound NOT as dynamic as the Yamaha (eg not as Beling Balang as the Yamaha)
result, keeping my Yamaha RX-V663
Looks like if I upgrade my amp, high possibility would be a Yamaha
My two sens worth

r u sure that onkyo 706 not as dyanamic as yr yammy ? then i have no comment lol.