There only 3 major battery manufacturers in North America,
Exide, Johnson Controls (aka: Interstate) and East Penn Deka.
Johnson controls is now manufacturing all their batteries including Optima's in Mexico.
There are generic car batteries now coming out of South Korea.
The lowest priced one's are a red flag they are either made in Mexico or South Korea.
When it come's to vehicle batteries, the only thing they compare test them all against the competitors is their Cold Cranking amps, This is a test done under refrigerated conditions for 30 seconds. Cranking Amps is never tested. Do not compare batteries on what they advertise what their cranking amps are advertisted.
Here is where it gets interesting:
When they make the lead plates that go into batteries, each manufacturer decides how much Calcium that they want to alloy into the percentage of lead. This is of course to keep the profit margins higher. Calcium is inert and is just a filler.
Now you would think: "OK they should all be close" But they're not!
In my 4 years of battery backround, I have picked numerous times, 2 batteries that are equal in specs and group size yet different mfg'rs. Yet each were significantly differential in weight. some of these companies are taking short cuts.
My conclusion was that I tended to find that the East Penn Deka batteries were consistently heavier most of the time I compared.
More Lead equals more reserve and a better lasting battery over the long run.