Water heater replacement, Atwood or Kuuma?

[pablosgirl]

While on the boat this week I noticed that the bilge pump was cycling and so was the pressure water pump. So the original Atwood water heater is shot.  Some online shopping shows that I can get the Kuuma 11812 from Hodges Marine for $297.05 and the Atwood marine S600 from Boat & RV Accessories for$385.09.  Both have the same dimensions with the rear heat exchanger connections.  Does anyone have any experience with either of these.  I am inclined to go with the Atwood since the original lasted this long. Does anyone have the Kuuma model and was it a drop in replacement.

[waughoo]

I have the Kuuma, but it came with the boat.  I have no knowledge of how old it is.