1500-ish in particular because I am given to understand that this was a pretty good century for both regions generally speaking and still before Europe's great divergence with the rest of the world.
I would say almost certainly China based on two very simple facts:
~1500 AD is in the middle of the Ming dynasty, and could likely be considered one of the golden ages of Chinese history. This is the period where Chinese philosophy, trade and science prospered (despite the leaning towards isolationism towards the end of the era). Being a super power of its time, China was also relatively unchallenged as a whole - those who lived away from the border regions enjoyed an extended period of peace during this time. It really wasn't until mid to late 16th century when the Ming began to feel the effects of foreign powers encroaching upon its influence and the attrition of multiple wars and civil conflicts.
On the other hand early 16th century was a very tumultuous time in Europe: England was just finished with fighting one of the bloodiest civil wars in European history. The rest of Europe is embroiled in constant smaller skirmishes between the HRE and its neighbors over succession and other (mostly religious) conflicts. You have the reformation movement which caused tons of unrest(which was inevitably bad for business). Italy saw the never ending Italian wars that kept on going until the middle of the 16th century. On top of that there were tons of rebellions all over eastern Europe (though admittedly this isn't something I've researched a great deal) which was also pretty bad for your health if you were an average peasant.
The 15th-16th century really wasn't a great time to be alive (even if it was an excellent time for historians to study) due to the sheer number of conflicts, schisms, revolutions and reforms that were going on all over Europe.
The important thing to remember is that China is not comparable to Western Europe--it is comparable to all of Europe, and then some. It has deserts, jungles, mountain plateaus and fair green hills. As Kenneth Pommeranz, who I somewhat suspect you have read because you use the term "great divergence"?, points out, a major flaw in a lot of discussion around the topic is that they compare a single region of Europe, say England, to the entirety of China.He makes a pretty good argument that if you compare the most developed region of China, Jiangnan, to the most developed region of Europe, England, during the early modern period you will see more economic similarities than differences.
This being said, I am not aware of any broad survey of biological metrics for standard of living for this topic, unfortunately.