I've lived in Tucson for 7 years and I love it here. I have a few friends that live in Flagstaff and have visited a few times so I'll try to give some input. Flagstaff is BEAUTIFUL, the mountain view is just amazing. Winters are cold and the spring and summer are pretty mild. If you love the outdoors then Flagstaff is a wonderful place, there are lots of great hiking spots. Sedona is also less than an hour away, which is one of the most beautiful places I've ever seen.

Flagstaff is a college town, the city isn't that big and the school is the 3rd largest in Arizona. Rent is a little high considering the size of the city (their prices are higher than Tucson). Flagstaff has an unusually high concentration of hippies and new age people. Sedona is believed to be some kind of Vortex (I'm not even kidding!), so it attracts lots of new age type and many live in Flagstaff since it's cheaper to live than Sedona.