The car I just sold had an AutoZone battery and it performed well for me for 4+ years and I am guessing will serve the current owner for a while yet. One thing I did before I bought the batter was to heed the advice quoted below from the battery FAQ and make sure to buy a freshly made battery (pulled from the back of the battery rack!):

"Unless a battery has been periodically recharged, never buy a non-sealed wet Standard (Sb/Sb) or Low Maintenance (Sb/Ca) battery that is more than three months old, a sealed wet "Maintenance Free" (Ca/Ca) battery that is more than six months old, or sealed AGM (Ca/Ca) or Gel Cell (Ca/Ca) VRLA battery that is over 12 months old, because it may have some permanent sulfation and lost some capacity. "Dry charged" batteries are shipped and stored without electrolyte. The electrolyte is added and initially charged by the dealer or the buyer. They usually have "sell by" dates of one to three years. Battery dealers will often place their fresher batteries in the rear of the battery rack or in a storage room. The date of manufacture is often stamped on the case or printed on a sticker. If possible, have a new battery tested to insure it meets or exceeds it's advertised specifications, and recharged if necessary, before it leaves the store."

Below is a link to the battery FAQ and to the really good section that tells you how to decode the various manufacturer's date stamps on the battery:

http://www.uuhome.de/william.darden/carfaq7.htm#freshness

Doug