Hiking: not sure why so many 5 star reviews. Its meh at best for avid hikers, probably stellar for beginners, though.
Biking: superb.
The road up to the summit is awesome if you like curvy roads. Just watch out for the cyclists who have no concept of MOVING OVER for vehicular traffic. Also watch out for motorcyclists who tailgate and cross over the lines.
The views are ok. It consists of mostly rundown south Phoenix and the ever-present smog layer. For better views go to Camelback or the McDowells.
The parking at the summit is very limited, be prepared to circle around a few times until a spot opens up. And the crowd that hangs out up there is, ummmm, interesting to say the least.