K read about it...
Before you buy, you really need to think it through...
Do you wish to spend $300+ on a battery grip which...
1) Allows another EN EL15 battery to be inserted, or 4 x AA battery? [Battery not included, including EN EL15 battery]
2) By installing so, you'll only improve the power-up time for your camera? Also taken into consideration that there are no improvement to any other functionality of your camera, no, no increase in FPS for continuous shooting unlike D300 and D700.
3) Gives you control over shutter, knobs and selection button even at vertical position. Perhaps making you feel good in grip too
4) Makes your camera look bigger and perhaps cooler compared to your counter parts?
$300+ is no small sum, you better think it over at least thrice...