You can (and should) pick up one of these things if you have a D90 or D80, and shoot vertically or need extra juice for the camera. The Nikon MB-D80/OEM model is a bit more solid, but you can't beat the Phottix's price!
Take a look at what's hanging on the neck of almost any professional photojournalist, wedding photographer, or camera guy—you'll almost always see the tank-like and bulky body of a Nikon D1/2/3/X-series or Canon 1D-series SLR. The Phottix MB-D80 takes your D90 (in my case—it also works on the D80, though) and gives it three of the tank-like bodies' functions:
A vertical shutter release/controls: When shooting portraits, this is immensely helpful.
Double the battery life: You can stick an extra Nikon EN-EL3e battery in the grip (bringing your total to 2 batt's!).
Look like a serious photographer: 'Nuff said.
The battery grip performs great, it can take a beating, and the shutter release and controls feel almost as good as using the controls on the camera body itself!
The video below is a montage of clips from Newport Aquarium in Newport, KY. I finally had some time to compile the clips, and back them with some ethereal music I had sitting on my drive. The video includes some jellyfish (even a tiny one that lights up its back somehow), turtles, coral reef plants, and a few other fish, big and small. All clips were recorded with my Nikon D90 at 720p, with a 50mm f/1.4 lens (it was DARK in there!).
The kit I'll be wearing at the Deaconate Ordination Mass this coming Saturday. Afterwards, I'll run to the back chapel, where I'll snap some shots with the D3 and a nice kit of SB-26 remote flashes!
Is anyone selling a used D3 for cheap? I gotta get me one of these cameras!
Gear pictured above:
Nikon D3 (rented from LensRentals)
Nikon 50mm f/1.4 AF (my own)
Nikon D90 (my own)
Nikon 70-200mm f/2.8 AF-S VR (rented from LensRentals)
I'm going to use the 70-200 on my D90, as the D90 has a smaller image crop, meaning the 200mm will be more like 300mm in practical use. The D3 + the 1.4 lens is a killer combo for in-the-dark shooting (the Cathedral is very dimly lit). I can still get 1/100 shutter speed at ISO 1600 and f/1.8!