Yeah. You should probably go ahead and bite the bullet now, as the price won't get any cheaper. I would strongly recommend spending the money on a R-410 (Puron)-based system, as it will be much cheaper to maintain in the long run as R-22 is phased out. As for efficiency, the best suggestion I can make is to factor the cost difference against your electricity bills, and see where the numbers play out. Don't forget to ask about any rebates your electric utility may be offering; those often offset the extra cost of the higher efficiency unit.