American Taxpayer Field, aka Citi Field, with its high fences and above-average dimensions is likely to be a pitcher's park.
Of course, until they actually play enough games to generate a material sample, no one knows for sure. At this point, though, I'd draft Mets assuming the park will play more or less like last year's.
Incidentally, the new Yankee Stadium has the exact same dimensions as the "House the Ruth Built" but it's hard to predict accurately how wind patterns will affect the flight of the ball over time.