HIked the Cholla Trail one evening with my partner on the recommendation of our hotel concierge. She, a Phoenix native, climbs it regularly in a reasonably short amount of time. I am not a Phoenix native and quit running regularly nearly two years ago shortly after I hiked Squaw Peak for the first time (shameless plug: check out my review). We did not climb Camelback as quickly as she did.
The Cholla Trail is a steady climb until the last hundred yards or so when you have to scramble up the side of the mountain to get to the top. Since we did a weekday, evening hike, we didn't run into much traffic so when we got to the top after an hour and 15 minutes, there were maybe a dozen or so people hanging out, only a couple more than we passed on the way up. It was nice because we had the trail practically to ourselves for most the time.
The Cholla in the late afternoon is an ideal hike because you spend most of your time in the shade of the east side of the mountain. The haze/smog/whatever you want to call it made for a disappointing sunset from the top. But it can still kick your ass.