Need help choosing a receiver in the $300 - $500 range. I have Polk monitor 90's and a cs2 for fronts, and monitor 40's for surrounds. needs to be 4k and at least 7.2 the features and specs on the 2017 and 2018 models seem very similar, but don't want to get caught by the old tech. blues. Ive been looking at these refurbished at Accessories 4 Less
Onkyo tx-nr777, tx-nr686, tx-rz720, tx-rz630
Denon avr-s740, avr-s940, avr-x2400, avr-x3400, avr-x2500
do any of these stand out or is there something else you would sugges