Now I have that thing, and do not want to give it back there. It significantly increases the comfort of the camera, as in particular the palm of your hand can rest on the side of the battery grip. With prolonged use, and when used with a heavy telephoto lens or an external flash, this is very important. And that puts all the issues for me. When I get along with one EN-EL3e battery autonomy, is the. Same in the battery grip and not only in the D300 For energy-intensive operations there then 2 batteries - one in the D300 and a grip. If necessary, you can operate the handle with 8 AA batteries or rechargeable batteries.
All in all - excellent accessory, processed excellent and a real asset in terms of comfort.