Doh-nut man,
I never ever hand brush a large area, no matter how confident I feel - I ALWAYS obtain better results spraying - I even get better results from a spray can than I do hand brushing, although I rarely use a can - I prefer to spray the paint into my airbrush jar using a short length of drinking straw as a funnel.
I do use spray can colors though, just make sure you shake the heck out of the can first, and place the can in a couple of inches of warm water for a few minutes to heat the can (you'll also heat the propellant inside the can, causing an expansion of the gas, causing an increase in internal air pressure within the vessel) - and by doing this you increase the atomisation effect of the paint coming out of the nozzle. It's MOST IMPORTANT you DON'T immerse the can in HOT or boiling water - you risk exploding the pressure vessel and paint will go everywhere and will pose a fire hazard.
Someone (rather indelicately) stated in one of these forums the other day - The last words of many rednecks - "Hey guys!! Watch this!!" Get the point?
Heating the can also helps the paint to lay down - you'll get a better finish.
Just practice on something to get the feel of how the paint comes out of the can and how it goes onto the surface of something before you test it out on your model.
Cheers
LeeTree