What's better than a Bradford White dual outlet (radiant and domestic) gas heater?

[packardv8]

The Bradford White dual outlet heater served well for fifteen years before the tank began leaking. This is a 65gal dual outlet; top outlets are traditional domestic. Side outlets serve the radiant heat in a sun room floor./

Since BW doesn't sell to DIY, what's the best alternative? Not looking for lowest initial cost, just longest life and most efficient.

jack vines