I agree. He's earned his paycheck this year. Despite the lower OPS, you could make an argument that Markakis is having a better year, though.
Markakis has over 100 more plate appearances, 68 more total bases, and 36 more RBIs in a worse lineup than Drew.
I know you're going to say that RBIs is a team dependent stat, rendering it meaningless. The Red Sox team OPS is .803. The Orioles team OPS is .755. Markakis is producing more with less around him.
That said, Fangraphs indicates that Drew is having much better year in RF than Markakis.