The brand of water heater that is the most reliable water heater is Whirlpool.
The Whirlpool brand of water heater is the most reliable and longest lasting water heater that you can buy.
You should be able to get 15 to 20 years out of a good Whirlpool water heater.
Another good reliable brand of water heater is Reliance which is a very good water heater that should easily last 20 years or so as long as they are maintained properly.
The other brands of water heaters that have good reviews and are good water heaters that are reliable are Rinnai, Ecosmart, Navien, Stiebel Eltron and Takagi.
Most water heaters you buy should be able to last between 10 to 20 years as long as you flush them out often enough.
You should flush your water heater every 6 months to at least once per year to keep sediment from building up in the water heater which can shorten the life of a water heater.