MANY individuals on different forums have talked about a problem with the quality of Optima batteries after their move to Mexico. From ehat I have read, many of these complainants were solid Optima fans UNTIL the problems came up. I am NOT sure if the problems still hold true, as that was 2-3 years ago, but I went with the Diehard Platinum (a rebadged Oddyssey), manufactured in the US. It comes with a 4 year replacement PLUS a 4 year pro rated warranty. It IS expensive (219 retail) but several times a year goes on sale for 179. Just a couple months ago, I was able to pick up a couple for 154 each. They are, in most poeple's opinion, the most reliable battery, along with the actual Oddyssey batteries, made by the same company.
Deka also makes an EXCELLENT battery in the US and they are sold affordably by O'Reillys. Deka is oem supplier to CAT equipment, so that says something right there. I am still running some Dekas in a dozer that are over 10 years old, and they still test fine.