[hayden55]

correct a traditional heat pump is the same thing as a mini split. The mini split is just also reversible and the traditional isn't. The technical term for both of them is an air source heat pump like how geothermal is actually called a ground source heat pump.
But you can just compare your summer cooling bills by seer rating if you plan to run both in default mode.
The old ac unit is just older tech so 10 seer vs 18 seer is probably a good one to go on. Winter is trickier.
But I did compare the 30k unit and the 36k unit with the inverter and variable output capacity and the minimum cooling outputs. The cop on the 30k with the 121 W fan was 4.29 vs the 36k with the 431 W fan at 4.41. So it looks like our question about messing with fan speed has been answered. Never mess with fan speed leave it alone.

They do multi head ductless systems so you just run cooling lines to each head and if you do a fresh build it can simplify the build and lessen cost.
But correct, ducts are premium air. If you already have them i would never downgrade to ductless. The main con to a ducted system is if they run through a non conditioned space like a hot attic you can lose a lot of heat or cooling as the ambient temp steals your btus on your duct runs. I have a bunch of basically free insulation though so im currently burying mine with the rest of my attic in R-40+ lol
Good enough for me.