Of course a higher efficiency condensing unit will cost more because it required more research and development and better manufacturing. 

It sounds like what happened is the AC evaporator coil was "installed" by someone with no idea what they were doing, and it proceeded to drip condensate all over the metal heat exchanger pipes (not sure of technical term) causing them to rust out..

If you prefer having one, which I do, helps for cleaning condenser coil, along with many other uses.

Moreover, one can put a dipstick in the tank coated with a water-sensitive paste to see if there is water in the tank. there is some condensation that is normal but if there is alot of water in the tank, it means the tanks contents could have leaked out.

What if we condense that down -- what about the level of headache and time of a one-city portfolio?

We found out through a previous inspection report ( two years back) on the house we are interested in, that the roof/HVAC (heater/cooling unit/condenser etc) are all nearing the end of their service life.

It seems a split condenser would make the most sense because we don’t have existing ductwork.

Things shouldn't go out, but faulty HVAC condensers are made every day.  

They just put a bandaid on each time until the condenser coils needed replaced due to corrosion but they tried to say it could be cleaned which was my responsibility, they were out at least once a year. 

It's a healthy and diverse economy with projected growth, but its also a city surrounded by open build-able land, which means it doesn't have the same kind of condensed urban core, where scarcity of land drives rapid appreciation like in other major cities.