I've been shooting the Asbell grip since 1986 and like it a lot. When I let other folks shoot my bow they always comment on how much they like the grip. It just seams to fill you hand and allow for an even spread of the bow weight accross you hand. It also make you grip the bow the same each time. Some folks say that it incourages a natural canting of the bow.
The Blackwidow web page did have a side by side view of the their grip and the AB grip. It is a fuller grip, so if you like small gips it not something that I think you will like but it's best to try one. BW does have a bow loner program that you could get a bow from them with the grip just to try out if you really wanted to shoot one.
One thing to remember not all Bighorn bows had the Asbell grip as they would build you other grip stiles if you wanted them and they did offer in the early years a high, med, and low grip as well as the Asbell grip.
DJ