I used to wear them when I first played, and when I played the WSOP
M.E this summer I wore them for day 1.
My thoughts are:
Wearing them makes you feel "safer"? I guess in a way. Its fun to be able to stare at people without them knowing you're looking.
You can do whatever you want with your eyes while the cards are out and they don't see what the heck you are looking at.
What I don't like is how its just darker in general, and may put more stress on my eyes starring. Also sometimes you get the wrong rep for wearing them (i.e. they may think you are SUPER tight and never pay you off, or think you are a fish and constantly come at you)
What I enjoy about not wearing them is its more intimidating and direct looking at someone. Especially when you have a shaved head like me