I put one on the front porch last year, saw nothing go to it, till one day I saw a hummingbird go around the house and sneak up on it. So they were going to it, but never when I was around.
I had a lot more luck with some wild honeysuckle in the backyard, they hovered around that stuff and you could get pretty close. I just put the feeder up again on the front porch, but even if I don't see them, I figure they are getting fed and will hang around some.