Eye sore or marketing tool?

I know you have all seen them on the side of the roads they are called glow signs and many business use them them scream deals out to customers passing by in hopes of luring them into their business. Large black boards with florecent colored lettering. What do you think of these, do they accomplish anything for you, do they draw you in or are they just a eye sore. I'm on both sides as the fence as a business manager I think they are usefull but when I drive down the road and see them every 20' it seems like they are becoming a problem.`