Hi, CarterZ -
First, may I recommend a good look at "Don Wheelers Airbrush," all kinds of airbrush info there, it might well lead you to a choice.
I use mostly Badger, if you need a dual action AB then either of those you listed will be fine. If you can do all that you need with a single action, then I would recommend either the Badger 200-20 or the Badger 200G, the latter being a gravity fed model.
For dual action, I use the 100LG, gravity fed. The Iwata is indeed a fine AB, I use one, but the Badger's are less costly and perform well.
Look for promotional sales at Chicago Airbrush, TCP and Webaire, I bought several of my Badgers for around $50-80 on sales events, they happen reguarly.
Good luck with your search.
Patrick