If you use soldering iron a lot and have the money, go with something like Weller soldering iron. Variable power and can last a long time.
I use a cheap one from Radio Shack, live time total of 2 the first one lasted almost 10 years before it died. The second (current one) has been used for 3 years and no failure yet. I go with cheap ones because I average about 100 hours of use per year since I left electronic repair business (50 hours a week back then)