Eddie,
I've never seen an air powered post driver but I'm guessing they would work like a pile driver - correct? If that's the case - I'm thinking would this air powered driver be any easier to use or any easier on the 'ol bod than a standard manual pounder?? Here, I'm slowly but surely replacing the wooden angle brace fence posts with T-posts. I bore a 2" hole in the bedrock with a portable (ha,ha,ha) jack hammer, knock off the T-post bottom plate, instal & follow with a sand/cement fill mixture. It's going to take me another 3-4 years to have all metal T-posts. And that only if that d**n jack hammer doesn't tear my arms off.