The GWH is a refinement of the basic Bruce Nelson Summer Special by Lou Alessi and Dane Burns, a design of which I'm very fond. The design works well for me because it's no larger than it needs to be, and it's a simple matter to don or remove the holster. The GWH has some features that I look for in a good IWB:
It's quite stiff for a leather IWB holster. This means the mouth stays open easily when reholstering, and it's not as easy to squeeze the holster against the gun; there is constant tension on the gun. As a result, presentations from the holster are faster than many IWBs and consistent.
The GWH is well-boned, attractive in appearance, and exhibits good attention to detail. It retains the handgun with the perfect degree of friction and puts the butt well into the body for maximum concealment.
I have one complaint: you can't straddle a belt loop on your pants like you can with a holster with two belt loops. This doesn't present a real problem for me with most styles of pants, and I am more than willing to make the trade-off for the stiffer belt attachment method.
This one came from Dane Burns about four years ago. I believe it's a special order item, though at one time Burns kept a few in stock for immediate sale. You can read Burns's description of the holster at http://www.carryguns.com/showcat.php?cat=Holsters