Hey, something to consider is what type of models you intend to build... you can use an airbrush on any type, along with some brushwork.

With armour and military vehicles, you can get away with just the brush, especially historical vehicles, as they don't usually require a pristine, high gloss,  "look, I spent the entire weekend polishing the bonnet and the chrome" look!

And like PM said, figure painting lends itself well to brush techniques.

Autos, airplanes and ships tend to have large areas that are harder to cover without leaving brush marks, so you'll find that a consideration; in the meantime, you could look at 'rattle cans', though you'll need a well ventilated area for that, or a space outdoors you can use.

If you intend to explore a few genres or just get in a little practice building before deciding, that's good too.