Like they said watch the overspray cause it goes a long ways. I found out the hard way that cars are a paint magnet. Sometimes the air/spray/wind swirls up and then travels a long way.
Around here most guys still brush and roll. A couple spray with airless. There is more spraying done on the interior as opposed to the exterior. The main beef is that paint sprayed on just covers the wood and brushing and rolling helps work the paint into the grain, cracks, pores, etc. of the wood so you get a longer lasting paint job where the paint won't chip and peel as easy. You could spray and have someone follow in behind with a brush and roller to work it in. It would be more important on the primer coat to get it worked in.
You shouldn't need to thin it. If so then get a spray rig that you don't have to such as an airless. Avoid the Wagner power sprayer unless your paint store will guarantee you won't have to thin the paint.