Practical Sailor (the CU of sailboats and gear) did a test of an air cooled Danfoss compressor system and a water
cooled Danfoss system. Considering the power required for the seawater pump, the water
cooled system only used less power in tropical conditions. So go with the seawater system.
But consider the Frigiboat keel
cooled system. It uses a passive block of bronze that is mounted on your hull
. Freon circulates through the block and condenses. So it saves the power and complexity of a seawater pump.
I have one on my boat and between its efficient controller that adjusts the compressor rpm
and the keel cooler
it used 1/3 less power than an air cooled system.