Rysta answered this question perfectly. Powertechs have SO much utiliy, mobility, AE threat, and are still able to take a beating. I love the mix of ranged and melee and the interesting variety of CDs. I also love the idea of the heat system, it's fairly unique out of other mmos I've played to have to worry about building up too much resource and I love the extra factor that heat management adds. On top of that, the animations are sick. Using Death from Above on a huge group of mobs never gets old. So basically utility, mobility, and the feel of the class.