Rattle cans are not too bad generally speaking ..if you keep the coats light ,brush painting is were the problem really arises ,using the brush you will pull paint into the panel lines ...you cant avoid it ,its one of those things .

If you can afford it ,an airbrush is the way forward ,not only for control ,but it widens your scope ,the choices for camo etc are endless you are not stuck to what you can make do with using the brush or tins ,not saying there is anything wrong with using brushes or tins ...just saying it holds you back a bit ,so if you can ...yes ,get an Airbrush ..you wont look back 

Chris.