Which Amp? Onkyo, Emotiva, Marantz, etc.

My 15 yrs old receiver died recently & I've the opportunity to upgrade. I'm planning to use Oppo BDP-105 in Pre/Pro mode in 5.1 setup.

I'm considering the following similarly priced ($1500-$2000) used/refurbished devices:
Amplifier: Emotiva XPR-5, MARANTZ MM8077, Onkyo PA-MC5500
OR
Receiver: ONKYO TX-NR5010, Onkyo TX-NR3010,YAMAHA RX-A3020, DENON AVR-4520CI & MARANTZ SR7007.

I do understand that the separate Amp would provide better sound & upgrade path but receivers will provide better functionality & features.

Which one would you recommend? I'm open to any other devices than the ones listed above.

Thanks for your time.