When Project Runway launched in 2004, competitive reality shows were in their infancy. Now, they're in their mature pantsuit years, but the series, now in its 18th season, rolls on. The show moved from Bravo to Lifetime, and last season it returned to Bravo with a new cast. Host Heidi Klum and mentor Tim Gunn have been replaced by Karlie Kloss and season 4 winner Christian Siriano. But the sewing machines continue to buzz, and it's still hard to make a dress in a day.