An affordable AV receiver is always a good option to consider, so Sony STR-ZA3100ES vs Onkyo TX-NR555 comparison definitely makes sense. Both have 7.2 channel amplifiers. Both receivers have support for Dolby Atmos multichannel audio format. The surround sound technology DTS:X is supported by devices. We have evaluated both AV receivers, STR-ZA3100ES has an overall score of 6.3 out of 10 vs 7 out of 10 for TX-NR555.
The Onkyo TX-NR555 is better receiver in this comparison - check Onkyo TX-NR555 price.