Summary: We decided to try a unit with a heat pump to replace our 1980's unit that conked out. It provides both heating & cooling. Our first few weeks living with the new unit have been very pleasant, much more comfortable and even temp control than the unit it replaced. It does seem to run most of the time though - must be related to the heat pump - so we're waiting to see how our electric bill compares with the previous unit.
Pros: Accurate Temperature Controls, Even Air Distribution, Quiet