AGM batteries are designed as drop-in replacements for old-school lead acid batteries, but have so many advantages over them. Gel batteries have their advantages, but are more specialized in their applications. Buying an OPIMA Blue-Top battery instead of a bigger, heavier, acid-spewing maintenance headache is one of the best decisions in camping gear purchases I've made to date, right up there with $500 Sierra Designs tents and $400 Marmot 650-fill down sleeping bags. Their higher cost is only at initial purchase due to longer lifespan and other factors - for me they are turning out cheaper in the "long run" due to quality and their many practical advantages over typical lead-acid batteries.
Comparing Marine Battery Technologies
