Another positive vote for precision control. While spray cans do have their use, I can't recall the last time I used one but it's been a while. With the cans you press the valve, whatever pressure and paint volume there is goes wherever it's pointed. The only control you have is the distance from the nozzle to the object, and the length of time the valve is pressed.
With an A/B you can regulate the pressure and the paint volume, a much better means of getting paint into tight areas, and layering multiple thin paint coats for appropriate build-up. Same for clear coats, paint volume control is just as important then.
I use single and dual action A/B's, I find they both have their own purpose in my spray booth.
The bulk of my airbrushing is done with a simple Badger 200G, single action gravity feed. Couldn't be easier for use and maintenance, cleaning takes a mere few minutes after use. Dis-assemble the front bits, place in small cup with thinner and clean with small brush, clean the body interior and the needle, wipe on some A/B lube, re-assemble it and it's ready for another day.
Same for the dual action models, with the ability to modulate the paint volume instantly by means of trigger pull, I can easily do freehand camo work and get into really tight areas like landing gear bays, cockpits, etc, with just the right amount of paint required.
When I got started years ago, airbrushing didn't go at all well for me for some time. For a while I wondered why anyone would want to put up with such disastrous results. Then I saw the great work of other modeler's, and stubborness made me keep at it. Finally the light came on, after countless dismantling, cleaning and assembling efforts, I came to understand the function and inter-relationship of the parts. Once able to make it function well, laying on the paint came much faster and easier to understand.
Please have a good look at Don Wheelers website, "Don Wheelers Airbrush," you'll find a wealth of valuable info there about types, use, maintenance, etc.
Once you get dialed in with one you like, I'll bet you'll never look back. Be aware though, your first one might well not be your only one. (Mine sure wasn't. (:>) Best of luck with your choice.
Patrick