Its all about Echo Canyon. My go-to side of Camelback Mountain, despite living a short walk to the Cholla Trail. Echo is shorter and more direct/steep/challenging, while Cholla is longer, more narrow and less difficult. For scenery they are very comparable, and they both meet at the top for the same killer views of the entire valley. For the majority of hikers budget about 2 hours round trip. Be careful on the way down, there are around 200 rescues a year and you don't want to pay that helicopter bill. For me Echo is a 26-28 minute high intensity hike to the top. It's an addicting exercise once you start timing yourself. A must do if you are in the Scottsdale area!