Best value 1/2" impact

I bought a Ingersol 2131 back in the early 90's and used it nearly everyday at work doing forklift repair for 11 yrs. then at home on car repairs and it still works fantastic today. Only one problem in all that time, the trigger broke. Cost $5 for a new trigger and was a 15 minute install. It is a very nice performing, lightweight and quiet gun that doesn't take a lot of air to run like most cheap guns (i.e. Harbor Freight crap) do. As OWDKASD mentioned, oiling them is what makes them last real long. Some oil before each use but I oil mine after each use. Seems the best way to to me as your storing it with fresh oil in it, not any moisture that the compressor put through it when you used it. But either way you do it will make it last a long life.

Keep in mind that you may be able to save money buying a cheaper gun but even when working on a car there are times when you might run into something rusted/frozen in place and the extra power from the better gun may get it apart where-as the lighter duty gun may not. For that reason I always buy the best I can afford and suggest everone do the same. Doesn't look like they make the 2131 anymore but they have a 2130 that's close to it. Here's the link to it

http://www.northerntool.com/shop/tools/product_200381617_200381617

Compare the specs then make your decision.