I'm not sure what your aversion to the BMW battery is.
In 160,000 miles and over 9 years, I only had to replace the battery once. The original battery went for 6 years and the replacement BMW battery has lasted over 3 years so far without a hint of trouble. Cost with the BMWCCA discount was no worse that other comparable batteries. I think the original was mase by Varta, not sure who made the second one.
Z