Until the last 3/4 of a mile of the ascent this is a relatively easy hike and doable quickly.  Our group took it slow and were still under 4 hours.  It is very narrow and can get crowded; watch out for mountain bikers the first 2 miles or so.  Several people had dogs; some lease, some not.  There was a lot of coyote droppings and it is known for rattlesnakes (although none were seen by our group) so I would advised leashed. We started at dawn and the hazy sunrise going east across the San Gabriels was phenomenal.  Going required a bit of scrambling from the peak but the first two miles are great for trail running.  Mt Disappointment is nearby and some others if you have extra time.