I replaced mine with the X2Power battery. There was a 20% off deal at my local Batteries Plus store if you bought it online and picked up at the store. I've also used the Deka battery in my G8, and the Odyssey Extreme (8 years old now with many winch and jump-start uses) in my truck with great success. I was told by my local battery "expert" that the Optima batteries are not nearly as good as they were before Johnson Controls bought the brand. Don't overthink it, just get something good.
Thanks for backing up my claim on the longevity of the Odyssey battery. You are in the same class of longevity with the North Star re-badge X2 power battery. Are battery post on the X2 solid brass?