There is absolutely no corrosion with the Optima batteries.
I replaced my last pair of Redtops just last winter.
They were 12 years old, one is still starting a Kubota tractor and the other running an electric fence.
Never had to clean the connectors even once.
They are the only battery I use now, 24 of them at last count on all the trucks, tractors and cars.
I have one on my Lincoln welder that was dropped 8 years ago and the case is gone, still works fine. Try that with a lead acid battery.
In my opinion they were well worth the extra price.