There is a flaw in the Consumer Reports about warranty of EverStart Maxx, it currently has only 3 years replacement no more 108 months pro-rate. I agree with Justin, buying/returning battery from Walmart is easy because they are everywhere, also all EverStart Maxx is at 1 price of $77 in So Cal. One of the biggest battery is group 49 at the same price as the smallest group size 51.
IIRC the best battery of one BCI group is DieHard Platinum, but it wasn't select as best buy because the price is too high at almost $200, while EverStart Maxx and Kirkland Signature are about mid $70's.