Excellent idea to go with a tankless water heater to replace your Atwood heater. Tankless heaters give you immediate hot water right away and use much less energy, so it's truly a major upgrade.
As for the best option, I recommend the Furrion tankless water heaters because they give you the largest amount of hot water - 144 gallons per hour - are designed more robustly than other heaters to withstand the movement and vibration that occurs in a trailer, and are easy to use with the included... view full answer...