What's the best modern battery for my Duster?

At our sawmill we have something like 35 batteries. The surprise here is that WALMART MAX Group 27 seem to out perform the rest. Most batteries, Napa, Interstate etc, seem to last 5 years with good maintenance. Walmart Max seem to last 7 or so. Ironically some of the others have a 5 year warranty and do last that long. Walmart has a 3 year, but outlast. Go figure. BiMart has good 5 year batteries, less expensive and a non prorated warranty. I've returned them at 4.5 years and walked out with a new one- no questions- not even for a reciept. Maintainers in the winter are critical for long life
Tried Optima. Worst, worst, worst battery I ever bought. Never had the CCA advertised and failed in a year.