Autozone has the replacement as well (Duralast), and we have had several members buy and recommend it. Probably what I will go with. Mine is showing it'* age at 5 years. I am prone to leaving my GXP under a cover for a week or two at a time. And find the battery dead. If I drive it frequently, it'* OK.
AC Delco Batterys are not of the rigid quality of years past. The Division was sold to Johnson Controls several years back by Delphi. They make average quality batterys and also make the Duralast.
In fact, they have pretty much stapled together the largest battery production Company ever. All these batterys are now the same as far as manufacturer and design, regardless of what color and label you may think better :
OEM GM, DaimlerChrysler, Ford, Honda, Nissan, and Toyota
AutoZone, Interstate Battery, Sears, Wal-Mart, and Costco
Carrying these Brands:
DieHard, Duralast, Interstate, ProStart, and Everstart
They also just captured the OEM Europe Market buying up HOPPECKE Automotive GmbH & Co.
They also manufacture the Optima Line of spiral wound/glassmat batterys.
Battery life and quality can be misleading because of the manufacturing process, time left in storage, and shipping and handling before it gets installed in your car. But most are same/same these days as shown above.