Mitchell, I really appreciate you taking the time to share your perspective. Totally agree that brand perceptions are formed based on positive or negative experiences. If a brand has a run of failures due to a failed component that definitely puts them in a tricky situation. Ultimately, the brand needs to have a long view and recognize that if they take care of everyone involved in those situations that they can do more to strengthen their position in the market.Best? Boy is that ever a loaded question. I've had a number of homes, and replaced water heaters in all of them as a homeowner (myself), as water heaters rarely give you a warning, "Hey, I'm about to crap out on you in 30 days, so best to get a replacement now" I've been at the mercy of getting what was available when I needed it..."in stock" as it were.
I've had a large number of brands as well, the most recent being Rheem. In fact, I've at AO Smith and Bradford White as well. I got the Rheem from a wholesaler as it was the best price and it was with the power vent I needed. I installed that in 2015 and never gave me an issue. It was a bit of an upgrade over the prior model in that it had a spark ignition, not a standing pilot. Before that, a Westinghose atmospheric vent at another home, in 2009, and that was a "5-Year" water heater, and it too, never gave a problem. In fact, all the water heaters I've had that have failed have done so LONG after the warranty period, thus little to complain about. I have never had a condensing model.
I did own a tankless, but not for domestic hot water but to power a heated driveway. The unit I bought for that was a Takagi TK3 199,000 BTU unit, because at that time (2009) it was the ONLY tankless manufacturer that certified their unit for circulating. All the other manufacturers clearly voided any warranty for circulating systems; plenty of folks were selling and using tankless for radiant heat systems and as soon as they did that, there was no warranty. That Takagi was still in the house used for the snowmelt system when I sold the home in 2019. Never gave any issue. It was not a condensing unit either. BTW, when snowmelt system is running, it was not uncommon for the tankless to be going at 100% velocity, (full flow and full flame) for 12-24 hours at a time.
Where I live now in NC, the most popular tankless are Rinnai. The builders seem to use State brand tank heaters. The builders even put in electric when there is gas available. (makes not a whit of sense other than to demonstrate how thrifty they are). With the former that may have much to do with local distribution and availability. With the latter, it has to do with the plumber's deals with the manufacturers. There's a Lennar subdivision of 300+ homes going in near me, and a savings of $100 on a water heater is an additional $30,000 profit.
"The Best" means different things to different people. A builder's greatest concern (and thus the plumber that subs for the builder) is to be the lowest price, and have no call backs during the home's warranty period. They also demand service and availability, and often will push that off on the distributor. A homeowner wants to balance price with longevity. If you buy a 10-year water heater, you sure as heck want it to last at least that long. I've had good luck with that, others have not. One problem with one branded water heater will taint you for life on the brand. Ditto with customer support that isn't; that is, squirming out of serving you, busy lines, unresponsive, etc. Nothing is more frustrating to a homeowner than trying to "get through".
A couple of pros have weighed in, and if they are changing thermocouples or heating elements regularly on one brand or another, they will, rightfully so, quickly form an opinion of the overall brand quality. Manufacturers are always changing the parts and sources for parts trying to make improvements or save manufacturing costs. Sometimes those changes backfire on them, and there can be a recall, or a slew of warranty calls. Nothing will taint a brand faster in the eyes of a pro than callbacks for the same thing, caused by a manufacturing change. Onto the next brand...!!!