I bought my second set of GC batteries from Costco this spring. I've been happy with all the batteries that I bought from them.
I had one Costco battery that went south, and that was in the truck. Costco has an outstanding warranty, I bought two new batteries, charged them up and swapped them out, took the old batteries back. I was expecting warranty on one battery, they gave me credit on both. I'd forgot the receipt at home, no problem the clerk scanned my card, found the original purchase and did the credit.
I would never go back to 2-12V.
When I was a kid I was going nowhere fast, now I'm an old man I'm going everywhere slow.