If you're picky about quality, do not order the aerosol kit. If you just want to spray some color, go ahead. The issue is you can't regulate the air coming out of the can so you get thick/thin spots that don't coat evenly or you get speckles. They sell an airbrush kit, but if you want to do more than one gun down the road just invest in a decent metal airbrush. The one they sell has plastic internals and it starts sticking after a gun or two worth of work. Plus the air hose that comes with it is junk and leaks like a shiv. If you have an air compressor already you can get a good airbrush for $60 - $90. Look at a Paasche H series, that's what I use for all my DuraCoat work, as well as other stuff I do such as R/C cars, laptops, knives, etc etc.
As far as the air brush goes, the one I recommended is a single action, siphon fed airbrush. This means you have a jar (or small cup) that attaches to the bottom of the airbrush and when you push the button it blows air plus paint at the same time. If you want to do a lot of small, intricate detail work a double action, gravity fed airbrush would be a better bet. With this your paint is fed from the top letting you conserve a little more paint due to it not being stuck at the bottom of the jar where the straw can't pull it up. You're going to pay more, but with a double action pushing down on the button gives you air flow and pulling back (while pushing down) gives you paint. It's kind of tricky to learn, but lets you adjust how much air and paint you get where as the single action gives you your preset air pressure and you adjust your amount of paint by turning a set screw.
EDIT: Another thing I wanted to throw out there is with DuraCoat, as with any quality paint, prep is key. If you spend 5 minutes prepping you're going to get a 5 minute prep look. Your best bet is to have everything media blasted, but if you can't do it yourself and don't want to pay someone to do it, then 400-600 grit wet/dry sand paper or a medium roughness scotch pad to scuff everything up is your best bet. Just make sure that you degrease everything well and wear gloves once you are done degreasing so as not to contaminate the surface again. I think I may do a write up when I do my 500 with some pictures.