It sounds like the Excel with the pilot light-less system is more "ABYC friendly". When Silverheels III was surveyed 5 years ago, our surveyor was very blunt in telling us that the Palomar wasn't acceptable (maybe it was back when propane was safe). I guess it depends on the surveyor whether it passes muster or not. Our insurance company also told us to get rid of it... The Palomar website states "not for use in boats or RV's".
We don't have a hot water heater on the boat now. A kettle on the stove works well enough for our needs.
Silverheels III N35, Toronto
Silverheels III Toronto Harbour, Canada