Heyward has one terrible season His numbers outside of 2011 are .268/.359/..457 (fulldiclosure, didn't calculate sluggin it just guessed since his 12-13 and 10 were right next to each other) Freddie is sitting at .285/.358/.466
Aside from Jason's bad year he and Freddie have been about equals offensively. Freddie has a higher BABIP, and that's the big difference.
Freddie has a higher BABIP because he hits nothing but liners and uses the whole field. I'm just not sure how anyone can watch the two play as much as you do and say that they are equals as hitters. The stats in baseball are phenomenal but they still need to be used in conjunction with what you are watching. My eyes tell me that Freddie is the better hitter right now.