I started out with the Eastwood dual voltage system, which was a great way to get started and understand the process. Upgraded to this machine, and it's sooooooo nice. The voltage controls give me a ton of more options and help with some of the trickier applications. But, the killer feature is the wide mouth nozzle on the gun. Max the voltage and spray without worry even if it's your fourth coat! It makes it almost idiot proof.
(As a side note, Columbia offers a class to teach powder coating which my son and I just took. 1000% worth every penny. Not only does Columbia make a great product, but they're great people. They've got my business for a long, long time!)