-The quality of tenant you can attract with central air is higher, and you will keep them longer because nearly everyone in STL is looking for central air if they can afford it but dont have it.Dont forget the AC cage to help deter theft of the copper in the condenser. 

Looks like the condensate drain line needs to be flushed out, which is just a regular PM.

In the SW, the 'typical' HVAC system is a gas Forced Air Unit for heat with an electric condenser for cooling.

I'm now replacing two high-efficiency condensing gas boilers that have corroded. 

We took a look at the house yesterday (entire block was closed off from traffic for the clean up and dumpsters, etc), and not only is the electrical panel cover rusted, but I am sure the HVAC ductwork/furnace/water heater were also all submerged, along with the central AC condenser outside the house. 

And LEDs don't last as long as they promise, of course.I love the idea of condensing dryers, but I see them right now as replacing something that can last 20 years with something a lot more expensive that will probably last less than half that. 

We’ve only checked condensate lines thus far because of some water accumulation in the ceiling.

@Peter Morgan most likely the duct above it or the connection between the duct and vent is not adequately insulated to prevent condensate from forming.

We would place the condenser on the roof so it would be out of sight and not an eye sore.The question: Since I'd be turning this into a modern home with nice finishes will the property appraise the same way regardless of if it has HVAC or a mini split system?

Just condensation for the roof/attic having no ventilation at all." and then said "We think it could be this.