I have 2 of the marine MAXX batts (series 29) for trolling and a blue top Optima for cranking. I also have a 3 bank onboard charger. IMO the onboard charger is as nice if niot nicer than the I-pilot is. I wont ever switch back to unloading batteries and hooking up chargers again, that's for sure. If youre planning on alot of longlining I recommend you hook two batteries up in parallel (for 12 volt system) so you will never run out of juice. You can troll all day and plug the onboard charger up that night and still be ready for another full day of trolling the next day with batts at full charge again.
Health nuts are going to feel stupid someday, lying in hospitals dying of nothing.