I have four airbrushes split between dual and single action. Well truthfully I have five, one is a duplicate other than needle size. They are all Badgers as listed, except for one which is a copy of a Badger:
- 100LG Medium needle (dual action gravity fed)
- 100LG Fine needle (dual action gravity fed)
- 150 Medium needle (dual action siphon fed)
- 200-20 Medium needle (single action siphon fed)
- 350 External mix siphon fed (clone)
I started off with the 150, and purchased the 350 clone for spraying Future (which it does remarkably well for a $10 airbrush!). Then I moved up to the 100LG Medium in order to be able to spray very fine lines (a technique not yet mastered!). The 100LG Fine was bought during Badger's Garage sale at less than half the price, along with the 200-20. I rarely use any other than the 100LG Medium. These are all considered "old tech" airbrushes, and they all share parts with the exception of the 200-20 which requires a longer needle and of course the trigger is single action.
If I was to start over today (or if I could justify buying one to SWMBO!) I would get the Badger Renegade Velocity airbrush, and be done with it!
Keilau's suggestion of that brush, along with the Iwata HP-CS and the Paasche Talon are all excellent suggestions. I would consider availablity of spare parts (needles get bent and washers get worn) to be every bit as important as brand. Check around to see if anyone supplies those parts locally, or order spares at the same time you buy the airbrush.
One factor in deciding is what you paint. If all you do is auto or ships, than perhaps the 155 Anthem or the 150 would be a good choice. If camo is your thing, then get any of the gravity fed versions.