I don't recommend Aztek based on reliability issues based on my experience with the double-action A430. I did follow all cleaning instructions and admonishments, unfortunately the body (not the any nozzle) seemd to clog up and needed replacement. A lot of people do have good luck with them, but unfortunately a lot, such as myself have had them die. Aside from the reliability issues, it worked well enough. Unlike a lot of others, I did find the unit to be comfortable to use, and the air hose location on the back of the body was not at all troublesome.
I have a Badger 200 siphon feed. It has a single action trigger, but a longitudnal double-action type needle, so it is easier to use but provides fine line capability. The only real problem I've had with it was one time I wigged while re-assembing it and bent the needles tip. Other than that, it is an excellent airbrush, easy to use, easy to clean, and aside from one moment of carelessness easy to disassemble.
I recently picked up a Paasche H for fun, and it too is an excellent airbrush. The first time i messed around with it, I easily painted lines fine enough for 1/72 armor and aircraft camoflage. Like the Badger, it is easy to use, easy to clean, and maybe even easier (at least less delicate) to disassemble.
Regardless of what airbruss you end up with, if you learn how to use it well, you'll get good results.