My experience with Gel Batteries from around 5 years ago unless the products have improved is there expensive, unreliable. ie Cells failing. Whilst these were be replaced under Warranty were applicable took weeks to get cells. Chargers expensive to repair.

Only problem with conventional batteries is over and under filling and charging. Hoppecke Track Air batteries are good reliable batteries but service can be a bit hit and miss depending on area. But generaly good Warranty cover. So would suggest going for a Track Air battery with a good Autofill system with Blinky Low level warning light and daily check and top up regime. Hope attached helps.