What resources do you have nearby? Sam's Club, Costco, Walmart, chain parts store, etc. I resolved some time ago to just go with batteries that meet the group and CA requirements, the longest replacement warranty, for the least money, that is most available. I replaced the original Delco batteries in my 2001 with Optima Yellow tops. They lasted 10 years, sort of. One of them quit at about 8 years, and I ran only the remaining battery for another 2 (solo). They did have a LOT of desert dry camping on them (no generator, and a lot of inverter use). Replacement Yellow Tops would cost more than 3X the Walmart brand I bought, and they've been going about 5 years. They are just now starting to show slight weakness, but are balanced and holding voltage. I expect to replace them again in a year or 2, probably with the same. Overall reliability doesn't seem to have suffered, at a fraction of the cost, and availability a non-issue.