The Red Sox are paying JD Martinez $24 million this season.

"Through the first quarter of the season, adding J.D. Martinez to the middle of the Red Sox lineup has been way more important than adding Giancarlo Stanton to the middle of the Yankees lineup."

J.D. Martinez is not an unknown entity.

He wasn't first in NL MVP voting 2017, and the expectations for his offensive output are certainly somewhat lower than Stanton's.

But Martinez was 14th in NL MVP voting, despite playing half the season in the AL

Perhaps that demonstrates typical boneheaded inconsistency by the voters ... I don't feel comfortable using MVP votes to support of reject any argument ... but it also demonstrates general awareness of Martinez's abilities.

Has Martinez been way more important than Stanton?

Probably a little more important.

Stanton has been kinda underwhelming, but also kinda productive in terms of HRs, RBIs, runs,

I think for $24 million, the Red Sox were expecting a great player.