christo

Have been to both, China much earlier, maybe that says something ?
Sounds like you prefer to go to Peru ?
Enjoyed them both, I'm sure you would too.
Went to Peru for Machu Picchu and lake Titicaca, both were absolutely, stunningly beautiful and awe inspiring. Cusco was a very pleasant surprise for how much we enjoyed it, Lima fine but not awesome. Been to Peru twice, no need to go back but China keeps calling me. Did a big tour of mainland once and for Hong Kong been there 4 X.
Sometimes it's the intangibles that make a country resonate with you, for China big time for us. It was a far richer experience than Peru (and I love Chinese food!)
In terms of travel ease I found China better and I speak some Spanish but no Mandarin.
Consider a cruise on Yangtze River to get out of the cities.
You mention crowds and noise of China, well Cuzco airport can be totally chaotic, Lima too. Altitude problems can be a problem in Peru and they are not to be trifled with.

As I have said to others, choose one then do the other later!
Bon Voyage.