Originally from Michigan; (grew up in northern Michigan.) Have lived in the East Valley area of Phoenix for a bit more than two years now. Yes, it really does depend on the individual and his/her lifestyle. For about three and a half months it's hot as hell...BUT for about eight and a half months (to my way of thinking) it's as close as you can get to paradise (temperature-wise.)
So, during those crazy hot months, my time outside is minimal. In the early morning, I might go out for a dip in my pool, but I'm either in the house, my car, or some other air-conditioned environment. I seem to tolerate the heat pretty well--when it's for short periods: from the car to the store or restaurant, etc. I know some people who really love the heat too. I definitely prefer this weather to the nasty weather in Michigan. I do love Michigan, but the bitter cold lasts far longer than Phoenix's worst heat in my opinion, and the gray, cloudy, drizzly conditions can have a depressive effect. On the other hand I can almost always count on lovely, golden sunshine here.
As someone who travels about 46 weeks per year throughout the country, I always get a kick at how someone can quickly size up a city. Just because someone drove to the airport in Phoenix does not give them a single clue about what is offered here. As you'll find almost anywhere, there are poor areas and there are great ones. I am by no means an expert on the area, but there are some positively gorgeous areas in Scottsdale and Tempe, and I'm delighted with how my neighborhood has been springing up. Although I've seen no signs of gangs myself, we can all imagine they must be here. I mean, Phoenix is the 5th largest city in the country now. 2nd largest in the western states after Los Angeles. It's entire metro area is 13th largest as well--at 4.6 million and growing. Would you expect gangs in New York, L.A., Chicago? Then why not Phoenix?
If you can't take the heat...best stay away from Phoenix--or at least enjoy it from October through May/June. But if you love gorgeous, mountain views, incomparable sunsets, hiking, fabulous dining--and all the other things that go along with a major metropolitan area--including almost nonstop sunshine, get here as soon as possible!