Propane is cheaper to operate but uses slightly more 02. We made the switch from acetylene over a year ago and have saved quite a bit of money. We are also an hour drive away from acetylene exchange and propane is available 5 minutes away. There is nothing I have found that propane can't do compared to acetylene other than save you money in the long run.
Anyone have one of those gasoline cutting torches? Looks impressive but you'd have to have a major job to justify the price : $1600 US version, $600 Chinese.