I use an Omni 4000 and a Badger 100, having bought the Omni 4000 first.
The single head set up on the Omni sounds attractive, but in reality
I've not found the Omni able to produce the same sort of results as the
100 with a fine head.
That's probably more down to my ineptitude than the ABs themselves, but
if I did it all again I'd probably just buy a Badger 100 LG with the
fine and medium heads and needles.
If you are only spraying small areas on gigures, then a gravity feed AB
would make more sense than syphon feed, given the amounts of paint
involved, and precision required.
Karl