I have mixed views on the grip. It id much better and of more robust construction compared to the grip for the D7000.
With two batteries - one in the camera and one in teh grip - it lasts forever. I was at 61% of my battery after 700 images wiht a long lens and lots of chimping and AF without shots. I agree with the comment about the multi selector - I don't understand why the multi selector on the grip is different from the camera in terms of feel. All in all, I like the grip and will keep it.