If your natural gas cost is low, then I don't see the increased cost efficiency saving you money. In our previous house, we had a State 6 yr warranted hot water heater last 18+ years. We sold the house before we had to replace it, and it was doing fine.
In our current house, we have State also, and they have lasted the 12 years with no sign of requiring replacement.
It looks like you got similar service out of your Bradford White, and I assume it was about a 6 yr warranted item also.
Electric hot water heaters is where the extra insulation, etc, makes a big difference, because of the increased cost of electricity vs natural gas.