Are you planning on the condo being a year-round residence, or a second home? If it's to be year-round, I would lean toward one with a monitor heater, and use it as primary heat, rather than secondary. Monitors are much more efficient than electricity, and create the heat much faster. Keep in mind the source of electric heat is likely as old as the unit itself - but the monitor is most likely a more recent addition. The age of the source will be indicative of it's efficiency.
Best wishes!