Air hammer advice

[Maxakarudy]

Hi everyone,
I've never used a hand held air chisel/hammer for anything less than ripping panels off cars, so I'm looking at buying a new toy!
Eckold do a planishing hammer for mind boggling money, I know know an old boy panel maker that swears its the best tool he's got, however I'm not gonna spend that sort of money on one £1400!!!.
Looking on eBay there are vast amount to choose from, I want one for planishing free hand not in a frame. Is there an ideal length or stroke to use or is it a personal preference thing. Are there low vibration versions that won't destroy your elbows with prolonged use?
What about the hammers are there fixed types that don't float around?