@f355spider for all your excellent advice.
If I had a do-over knowing what I know now, I'd have bought a 24F Walmart Everstart Economy battery to get the lowest price of $80 and it would still have been a more powerful upgrade compared to buying a 51R Everstart premium battery for $150.
Since I'm on the Westcoast, it would have been a Walmart Everstart made by Clarios. That would be fine. Clarios makes the Honda OE batteries and they're excellent. I just learned today from a Honda dealership that the Honda OE batteries are made by Clarios.
Honda dealerships charge $12 to $20 more for a Honda OE (Clarios) battery than the cost of a similarly spec'd Walmart Everstart (Clarios because I'm on Westcoast). If I was on the Eastcoast, a Walmart Everstart would be made by East Penn.
However, Honda OE battery has a 5 year warranty (3 years full replacement, followed by 2 years prorated) and my local Honda dealership will install the new battery for free if it's located in an easily accessible place under hood. However, free replacement would not cover upgrading to a 24F battery.
So what's the best way to go depends on what the individual wants, the level of convenience they want, and how fast they need to get their car back on the road.
It's debateable whether Clarios or East Penn is better, and also debatable if it's enough difference to matter when they're different prices. In my local Westcoast area, Walmart Everstart Clarios cost $20-40 less than Oreilly Superstart East Penn when comparing 24F batteries with similar electrical specs.
I thought East Penn is likely the best flooded battery, but that's just my best guess opinion based on info I was told in a PM by a prominent member. IRL Clarios may be just as good. I don't know. Both are excellent and prices range from excellent to OK to high depending on who you buy from. Warranties range from 1-5 years depending on who you buy from.
I bought an Oreilly Superstart 24F for $120. My neighbor is thrilled to have an upgraded battery. So I'm happy too. That said, if I knew more sooner, I'd have saved $40 buying a Walmart Everstart Clarios. I did save $30-40 compared to buying an Everstart 51R.
Could I have done better at saving money? Yes. I could have save another $40 more by buying Everstart from Walmart. But I still saved $20-40 by upgrading, am getting an upgraded result, and my neighbor is thrilled! So mission accomplished.
Thank you
@f355spider,
@Nukeman7 and others for excellent advice.