In my experience AGM batteries fail more often than acid-filled old-school batteries, I would only run an agm/gel if it was inside the car and not able to be vented. I agree with the others in a Costco battery, even Wal-Mart is fine as I used an EverStart in my old YJ Jeep, it was cheap, held its charge over the outside winter slumber, and was good for the 4 years I had it.