Well, that's a broad question. It really depends on what kind of application you're using it for.
The paint in spray cans generally has larger particulates, meaning it won't give as fine a finish as paint formulated for airbrushing.
That's just for spray cans overall. There are some more expensive spray cans that will give a very fine spray, such as
Tamiya fine surface primer. Man, that stuff sprays on smooth!
For choices in colors, you can't beat airbrushing. Spray can selection is pretty limited. If you've ever walked into a (good) hobby
shop and seen the selection of model paints, just consider that any one of them can be thinned and shot thru an airbrush. It
also opens up the possibility of color mixing, and coming up with a huge number of custom colors.
If you're going to be doing weathering or detail work, an airbrush has the advantage here, too. A spray can only has one
setting: spray.
I know there are some that have different buttons you can snap on the can to adjust the pattern, but
none of them will adjust enough to give good, controllable definition.
One initial drawback to airbrushing is the expense. But after you've bought the airbrush, and an air system, it'll last for years.
Those are just my opinions. I'm sure there are a lot of members who have preferences either way.
