Mini-Split Ductless Air Conditioning vs Replacing Existing AC in Condo?

I live in a 1br condo with one of those combination gas furnace/AC Magic-Pak units. The AC part of the unit is no longer working, which means the whole unit has to be replaced. I haven't been impressed with the unit when it was working it was noisy and inefficient. I'm looking into a mini-split ductless air conditioner as a possible alternative to replacing the Magic-Pak. I would like to know if this sort of system would be either more efficient or less expensive than a new Magic-Pak. I've been quoted an estimate of about $4000 for replacing the Magic-Pak.