Exide has went through Chapter 11 bankruptcy protection in 2002 and in 2013. I wonder if this has caused them to have more quality control issues, especially if they were cut off by any suppliers or reduced staff to try to stay afloat.
Battery life overall seems to be a regional thing. Batteries up north can easily last 5 or more years, but you're lucky to get 3 in the deep south. Heat damages batteries very quickly. Cold weather, on the other hand, is very good at making an already bad battery fail to start the car.
Exide's issue seems to be quality control... lots of posts about leaking / corroding terminals and sudden failures on less than 3 year old batteries. Seems like they work OK as long as you get past the first year and a half or so. Lead acid batteries are old technology and should not be difficult to make without too many duds. Every brand has occasional issues, and some of these may be due to stores not rotating stock properly. I have seen batteries more than a year old on the shelf at Wal-Mart, and I have my doubts they have been charged every few months to prevent permanent damage.
Until I stop hearing about short lived Exide batteries, I will continue to buy East Penn or Johnson Controls, in that order, with the most recent manufacturing date. Of course sometimes there isn't a choice and you just have to get what is available on a Sunday night away from home when a previously good battery suddenly develops a shorted cell.