The WalMart batteries in the Iowa area used to always be Johnson Controls, fully sealed lead-calcium construction. They seemed to last forever and like most sealed L-C batteries did not corrode the terminals, battery box, etc. I have had several, including the cheapies that lasted a long time. The Exides were always the "low Antimony" lead alloy, they took much less water then 1950 era batteries but still took some water, eroded the terminals due to outgassing.
Now, we only get Exide manufactured batteries in this area. The Exide Lawsuits (Sears, US GOVT and mail fraud!!) around 1998 showed huge manufacturing problems and very high failure rates, Sears tracked their warranty returns for Exide vs Johnson Controls, etc.
Now Consumers Reports ( which in the 1990's identified about half the new Exides in their tests were already defective) has now declared Exide to be acceptable. Note that most Exides in the 90's they tested were "working" but revealed huge variations in starting power. The cause was poor assembly, cracked internal welds (remember lots of plates in each Cell) Those with disconnected plates failed very early in life as the lead distribution soon becomes untenable within each cell.
I wish WalMart could get Johnson Controls batteries back in the area, although the Exides may have greatly improved their quality. All the new Japanese cars in this area get Johnson Controls batteries, NOBODY - that I know of- will use Exides for orginal equipment.
Looking for updates/additions to the above information!!