I too, was once a dyed in the wool Diehard battery guy. They'd spin the motor over like nothing else. But - they'd never last more than a couple of years. Sear's replacement warranty made that a non-issue. No more though.
So - I've changed to Interstate on everything I own, other than my Harley. Seems most other brands of batteries for Harley's are slightly off in size, post position, or whatever. And, although pretty expensive for a tiny battery, they do last very well. Over 7 years on my last one.
I did have good luck with AutoZone's DuraLast Gold batteries, however there are no AutoZone's nearby, thus the switch to Interstate.
Remember the old J. C. Penny's batteries with a LIFETIME warranty? After replacing mine 4 times - they shut that deal down
I sure can't believe how the price of batteries has jumped in the last two years though. I was told that it's a shortage of lead. Haha - not likely!!