This is one of those gadgets that are just too handy. Hand straps are useful in those situations where a neck strap just gets in the way or when the camera is constantly going in and out of a pack. Personally I generally dislike neck straps. Having a D200, grip, and long telephoto attached hanging on my neck while hiking or snowshoeing is not my idea of fun. After a short while it begins to really weigh you neck down and drives me nuts. Never mind the fact that I generally don't trust those quick connects on neck straps; they tend to unclip when they snag on something and it's always when you least expect it. Neck straps tend to get in the way when they are not being used, and are often the cause of a dropped camera if they snag on something, not to mention scratching your LDC screen.

The Nikon AH-4 is a very nicely crafted soft leather 3 point hand strap. It comes with it's own camera body plate adapter unlike some of the other straps that are available. The strap does fit full size bodies as well as smaller ones like the D70 and Canon 30D. It will also allow you to have a neck strap attached at the same time if you wish.

The strap is very easy to put on and take off. Once your hand is in it, even letting go of the camera means you will not drop it.

The only drawback I have found is that to use the strap with an arca style quick release plate requires some modification. I have a Markins camera plate for my D200+grip. The eyelets are too small to accommodate the fairly wide strap. Also the end of the strap has a rubber grip section on it which prevents it from being inserted through the eyelet in the camera plate. To resolve this I found some nylon strap material of the correct width and sewed a loop of it though the camera plate. The AH-4 strap then goes through this loop and your problems are solved. This also gives you a bit more length of strap to grasp when you are tightening the hand grip.

Overall this is a very good design and I would definitely recommend it. 

Cheers