I have been hanging around Lawson's shop for over 20 years, here in Tucson. Harry Lawson was one of the first to develop the thumbhole. I can only speak for his version:
The grip area is angled and I think this is a more comfortable position for the wrist. As for the safety, Lawson has a crossbolt safety built into their triggerguard. There is no drop to the comb area which helps deal with heavy recoil. Their recoil pads are cut wider than the rear of the stock and are sanded in a gentle curve to meet the wood. The extra surface area helps spread the recoil over a larger area. Finally the stocks are not necessarily heavier than a conventional wooden stock. I have heard more that one owner say their Lawson stock is very fast at acquiring an animal in offhand shooting. I believe it has to do with the Lawson style as most are shorter lighter barrels as well as the fit of the wrist angle. As said before they are different. Personally I don't have one and don't know if I ever will, but I can appreciate what Harry has developed.
