You do get what you pay for, sometimes... NAPA used to help us sell ACDelco and Motorcraft batteries when they used Exide. The reputation that NAPA got from the warranty issues still helps us sell batteries Interstate is one of the most expensive batteries on the market (someone has to pay for all the cars that Kyle Busch wrecks... ). They are built to Interstates standards - and the quality of an Interstate battery is a result of those standards. They used to be known as a very high quality battery, but just this week I picked up two more battery accounts that had been diehard (no pun intended) Interstate customers for years. Price, warranty and service issues were the reason. A top of the line ACDelco 78 series battery (made by Johnson Controls) has a 42 month free replacement warranty. The top of the line Interstate 78 series has a 30 month free replacement warranty. Repair shop cost for the Interstate MTP 78 is about $20.00 higher for than the ACDelco 78PG.