I've made the switch from lead-acid batteries to gel and am very impressed. As an ex-navy electrician by trade and avid downrigger fisherman, I can tell you that the new gel cell batteries are the best batteries that have ever been made available to the public for this kind of duty.

Here's why. Bottom line, they can deliver more amps for a longer duration than their lead-acid equivalents through the technology built into the gel cells. They will last longer and require less maintenance. And in the long run, will probably cost less than lead-acid batteries even though they cost more up front.

You should always get a marine deep cycle for downriggers and other loads with a significant sustained draw like an electric trolling motor. The deep cycle battery is made specifically for this duty.