The general rule is to buy highest quality tools. However, on pneumatic tools and electric tools I take a more nuanced approach. If you can afford Snap-on, by all means, go for it, but if you don't use pneumatic tools very often, the cheaper ones will probably outlast your intended usage. I'd go for the Craftsman or equivalent. The one area not to go cheap, as MAD IN NC related, is on the 1/2" drive impact sockets. Those take a real beating, so get the best. A 3/8" drive air ratchet can be real handy for getting off fasteners where you don't have a lot of room to swing the ratchet--if you can get the socket on it, the air ratchet will make quick work of getting it out. The air ratchet also doesn't beat the sockets as hard as a 1/2" drive impact wrench, so you can get away with using the standrad sockets you already own. I have air tools, but I only use them occasionally, or when a fastener is really stuck.