Why hole in the rock is a popular spot is beyond me? I suppose it's neat to be out in the desert and once you get to the hole you can see Tempe, but that's about it.
The hike itself is extremely short, anyone can make it up in no time at all. If you are looking for a decent workout or solid hike this is not it. Once you get to the hole in the rock you expect it to be amazing since it is popular, but instead you'll find a mess of shattered bottles, food wrappers, and trash. If you go when it's hot or at an off time you'll be able to enjoy the view, but if you go during prime time you'll battle a crowd of people. I find it to be exceptionally busy on holidays when people who never work out decide to go for a "hike" because they feel guilty about what they ate or are about to eat. I've even seen people take their kids in strollers up to the hole.
The Arizona desert is beautiful and you can see the beauty here, but it is dirty, not well kept, crowded, and not much of a workout. There are plenty of other wonderful places nearby to take in the view and get a decent hike. Don't fall for the hole in the rock tourist trap.