I have a 400W Air-X that came with the boat. It's been trouble-free for 5 seasons.
The PO bought it for an extended stay in the Bahamas. There, with daily +15kt breezes at anchor, it made sense. He frequently saw outputs of 30Amps, and was able to operate his cold plate 24/7 without having to plug-in anywhere.
Here on the Chesapeake, with our light-air summers, its a different matter. On a typical sail (when there's enough wind to sail), I see about 4 or 5 amps out of it. Not much, but it's basically enough to offset the power used by the radio, GPS, and autopilot.
I'm glad I have it, but would have never spent my limited boat-bucks on one for just here on the Chesapeake. Solar panels would make much more sense.
Depending on your location and intended destinations, YMMV!
