I also used to use an Aztek and replaced it with an Iwata Eclipse HP-BS and am very happy with it.
It has a well-balanced feel, easy to clean and performs well.
I got it for $89.95 delivered from Dixieart.
If I had it to do all over again I would buy the same unit.
Our unofficial airbrush guru (although he staunchly denies it!
)MikeV is a big advocate of the Thayer and Chandler/Badger Omni series as a less expensive alternative to the Iwatas. Remember to consider the cost of replacement parts as well.
This is just my 2 cents worth since you were asking for units to consider. Take your time with your research and you will end up with the right airbrush for yourself.
Merlin