I'm getting ready to replace my Rheem 75 gallon gas water heater with a
Kenmore Power Miser of the same size.

However I noticed that the Rheem has a rating of 75500 input BTUH, and the
Kenmore has rating of 55000. I'm not clear if a loer or higher number is
better, as some explanations I've read seem to indicate that the Rheem would
use more BTU's to heat the water than the Kenmore (thereby making the
Kenmore more efficient).

Is my reasoning correct or is the reverse actually true?

Thanks in advance.