I really prefer a bell. There is something infinitely cool about hearing the bell ringing and knowing it is okay to hit.
My former home club in Virginia, CC of Fairfax, is famous for its blind tee shots. #5, #7, #8, #16, #17, all blind or semi-blind, and the second shot on long par 5 #5 as well. CCF really could use either bells or periscopes but has neither. Only a private club, where the members know what's out there, can afford such shenanigans!