So no, this isn't a Phoenix must-do. But it is short, easy walk up to a nice view of the city. Would I bring family or friends to do this? Nope. It's pretty, but there are other places that are much prettier and much more rewarding.
Just a heads up that there are no signs pointing the way. Your best bet is to drive into the zoo parking area and take a left toward the picnic areas. Keep going til you get as close to the hole as possible. There's plenty of free parking so that shouldn't be a problem.
I would have to agree with others that this is no hike. Unless you count any kind of short walk a hike. No chance of getting your heart rate up here. But I would recommend wearing some tennis shoes...or something similar. The rock is actually a bit slick and you don't want to face plant like the guy I witnessed. Pretty brutal.
Enjoy the view!