Rheem corporation, which makes water heater under the brands mentioned, and HVAC under Rheem, Ruud, Duroguard, and probably other brands.....is a Division of the Paloma Corp. ( Japanese ). Rheem stuff is all genuine American ( North American, that is, mostly Mexico).
Rheem is well respected. The GE models in the depot are a slightly cheapened up version of the Rheem branded models.
As far as all the other brands, there was a time ( pre 2003) when you could not make a good case about significant quality differences. Every brand makes a good-better-best assortment. I had a State in my condo for 17 years , and I replaced it just because it was old. It was still working. State was basically a builders brand, middle of the road, but it held up.
Then came FVIR in July 2003. Rheem, and probably Bradford White, invested significant engineering into the design to ensure their units would not have the failures and maintenance issues which the Whirlpool is classic for.
It seems the same thing has happend with the Ultra Low Nox water heaters for SCAQMD. Rheem got the design right, others....we'll see.
If you are shopping for a water heater, you should have the point by now that the folks here would recommend a Rheem, or GE, or Bradford White. The principal risk with the GE if you do it yourself, they have some incidence of damage in handling in the store. If you take home a bummer, you will be on the hook for the labor to uninstall it and take it back for a swap.
