I have an Aztec dual action airbrush, I have my praises and complaints about it.
Honestly though, I've found myself gravitating back to good old brush painting. Its nothing to do with my airbrush, its just that with a good selection and variety of brushes and a bit of knowhow with various brushing techniques, you can come away with a very well finished model.
Lately, I've been using my airbrush only for primer coats and subjects that are only one or two colours. Any more complex than that, and I just don't feel like going to the trouble of setting up and tearing down the airbrush.
I guess you could say the novelty of the airbrush largely wore off on me and I got back to basics.