Its a toss up between the spydie hole, and the thumbstud.
I have to say I think the better using blade has a hole!!! sometimes, but rarely, the stud can get in the way of cutting taks (depending on the knife configuration).
as far as the nailclick, well it is nice to play with one once in a great while, but ever since I bought a tak fakuta back in the 80's with a stud Ive never felt the same about the nail click since.