Refrigeration
I am installing the cool blue system on my E-35. I gave both the evaperator plate and holding plate systems carefull consideration. Both cliam to be more efficiient than the other. I guess it depends on how you will use your boat, day sails or long distance cruising. For daysails maybe the evaperator plate is better. But I am looking for a system that will run once or twice a day not cycle on and off all day. While cruising or long distance racing I run the engine about every other day. This means I can freeze the holding plate while the engine is running and take no energy from the battery. When I dont run the engine the battery will do the job. With this in mind the combo unit, engine driven and DC would be the best choice, but it costs alot more and the E-35 dose not have room in the engine compartment for anything else.
The Frigoboat system uses the keel cooler in some cases. This seems like a good thing if you dont mind more holes in the boat. Other than that it seems to be just a European model of an Adler Barber unit.
The most important thing no matter what system you choose is insulation. You will want to add or re-insulate you box as the factory job was not good enough. You should read what Nigel Calder has to say on the subject in his book "Boatowner's Mechanical and Electrical Manual" Mc Graw Hill.
The best price I found on Cool Blue was at Jack Rabbit Marine.
Good luck
Phil