I wish it were a simple question to answer. These days, all HVAC systems are expensive. Sometimes this is due to the system itself, and often this is due to overcharging practices by HVAC companies. 

The question of “best”, however, is dependent on your climate zone, your heating and cooling needs, and your preference of electric vs natural gas-powered. If you live in the southeast region of the US, you have a lot of outside heat and humidity. The desire / need for cooling is the standard. If you live in the western part of the US, you typically have more arid conditions until you reach the coast of northern California, Oregon, and Washington. 

If you live in a humid region, mold growth is an issue with or without a version of heating and cooling, but can be made much worse if you have a system that is not right for your climate zone and / or is not properly maintained. 

The bottom line is always performing proper maintenance for any of the systems. As a homeowner, I just want the system to work efficiently and to not break down. As a home builder, my focus would be on how complicated or easy it is to install the system and then whether it will be properly maintained.