If you are measuring their first 3 seasons (both at age 23. , then Stanton is clearly better based on defense.
I might not value defense like you do but IMO, you cannot compare an OF to a 3B. And I get tired of hearing "well this guy is more valuable because he plays CF and this guy plays 1B." I bet that CF cannot play 1B effectively..
In the end I don't see them the same hitters. I see Stanton as more a power guy but not hitting near .320. And getting OB as much.