With a thumbhole, your hand and wrist are more vertical and inline and more comfortable to me.
Also, the thumbhole reportedly allows you to absorb more recoil in your hand and arm, distributing it, rather than centering it on your shoulder. Kind of like the front pistol grips on a defense/turkey shotgun.
Finally, handling a rifle one handed while hunting should be more comfortable and secure.
All this if the stock fits your LOP and hand. It might take some getting used to, but I think the comfort would be worth it.
Besides, I just want one.
Anybody use one on their everyday rifle?
pepaw