Plumber quoted me a 40 gal Rheem Fury which has a 6 year warranty. He said his supply house does not offer one with a longer warranty, which I understand just means a bigger anode. From the forum here, it looks like Rheem is good, but is a 6 year heater good enough or should I look for a plumber that can get me a model with a longer warranty? Worth the extra expense? TIA!