Gents -
Some good points and as usual some interesting ones:
First, high, medium and low grips have been used quite successfully over the years, so to say one is better than another, may only be true for a given person AND at a given stage in their shooting career. (I've gone from high to low to medium and back several times over the years and currently doing quite well with the low grip.)
The high grips main plus is the potential for, but not the elimination of torque. Some people are quite ingenious and will torque a bow regardless of what kind of grip they use. The advantage of increased bone support is more theoretical than factual. It's biggest short coming is that unless (bow) grip is specifically designed for that hand position is it the most difficult to maintain over long shooting sessions. It is also the least stable (smallest pivot area). Yes, it can become painful, especially with some of the extreme variants.
The low grip is the most solid and therefore the most comfortable. Think about having to push a refrigerator with sticky casters. It does require a little more thought to reproduce consistantly and MAY increase the torque potential, if not done correctly. Once established, it's pretty hard to beat for consistency especially over extended shooting sessions. Torque becomes non-existent when a low grip is used with an open bow hand and sling.
Using the same bow, the difference in draw length should be minimal, with the only possible exception being a straight grip longbow, which IMHO, would be brutal to shoot with a high wrist.
Basically, pick your poison and develop it until you perfect it or need to try something else.
Note: really need to be clear if you're taking about BOW GRIP design and/or wrist position. You can and some folks DO use a low wrist on a high grip and quite well, I might add ... might even be the bst of both worlds - for some ...
Viper1 out.