These systems should be less complex than a comparable air source system.
The geo system can be simple or complex. Generally the forced air is about as complex as furnace.
Floor heating is another story altogether. Since there are many floor loops it is easy, if structured properly, to zone each room with own temperature control. The HP also heats HW so that loop also has to have a temperature control loop and has logic that disables direct heat when heat from HP is available. The heat/cool accumulator also has to have own temperature control. Then there is AC with its own temperature control and there is logic switching between heating/cooling. Because of large time constant of the floor heating (0.5 deg/hour) the mode of operation can't be changed forth and back like in forced air. My system uses high pressure AC that works very well but it makes whole house filter integration difficult. So there is logic in the system associated with that etc.
The big variable with ground source is that the engineering and installation of the loop is critical as that is not pre-sized and tested by the manufacturer.
If you put the loop in the pond the biggest expense it the underground line from the house to the pond. So if in doubt add more coils in the water. It will increase the cost only marginally. Ground loop is another story. Over killing it will not improve or hurt the function but hurt you pocket.
