As stated by several others, most batteries are made by Johnson Controls or one other company, that if I remember right, is Exide.

Given that, the issue comes down to who will back up the warranty the best.

I've had two Interstate batteries and two bad experiences.

Years ago I got an Interstate for my VW Rabbit diesel because my friend sold them in his body shop. A few months later, I went to start the car and the battery blew up. No replacement. "You have a problem with your voltage regulator." Right. The Diehard I put in lasted until my ex wrecked the car five years later.

When I bought Guderian back in 2002, he (great topic idea! Gender of your car. I'll start it after this post) had a new Interstate battery. After a week of ownership, he wouldn't start unless it was a jump start. Then it was within a second of turning the key.

After a jump start, I went to the Interstate battery dealer. They tested everything. Their conclusion was I had a bad starter and the alternator was marginal. No replacement. A new Interstate battery was something like $125. I went to O'Reilly's got one for about $60. The car fired up instantly every time after the new battery was installed. It is still running with the same starter and alternator.

Two years two months later, same problem. Took the battery back to O'Reilly's. No testing. The manager said it was close enough to the two year full replacement that it wasn't worth fooling with the pro-rated portion of the warranty. New battery for free. It has been a champ since then, going weeks at a time between starts.

If you need a battery, go to O'Reilly's. They back up their warranties, have good prices, and usually have series 47 and 49 batteries in stock.

This is from someone who used to work at a NAPA store and would go to NAPA for most anything else.

__________________
1983 300SD "Guderian"
1987 MR2
2015 Camry
2015 Chevy Spark
2006 Hyundai Tucson