Airbrushes are very personal, like pistols, cars, underwear, etc...

What will you spray? I have three brushes, and Iwata Eclipse, an Aztek A470, and a Badger 175. I like the Iwata hands down over the others for spraying enamels. I like the Badger best for Acrylics. I dont use the Aztec much...
The advantages of the Badger are flexibility and ruggedness, along with good value. Disadvantages are weight and workmanship is not as good as Iwata. Harder to clean.
The Aztecs advantages are ease of cleaning, light weight, low cost, and flexibility. The disadvantages are ruggedness, ease of use, and light weight. (It is TOO light)
Hope this helps. If you want my personal opinion I would tell you to get an Iwata and spray enamels.
Hope I helped...
Scott Gentry