The vast majority of batteries are made by one company - Johnson Controls. They private label, and may build them to different specs for different brands, but I am of the opinion that for the most part, they are the same. So I buy the ones with the combo of best price and best warranty - which usually means something from either Costco or Walmart.
To answer your question on battery life, I think that can vary wildly. I had a 2003 RAM CTD that I bought new in December of 2002, and sold it in September of 2011. It had the original batteries in it when I sold it. It had around 120,000 miles.
My current truck, bought in September of 2011 needed batteries at 3/20/16 at 46,321 miles.
