Being that it is winter and I have nothing better to do but research what batteries I will use to replace my old ones with I came across the AGM, or Absorbed Glass Mat Batteries. Has anyone used these? In an article I read they stated that AGM batteries are as good as the Gel style batteries if not better. They cost about the same, but the thing that caught my eye was they offer them in the same physical size as my existing deep cycle battery which means I don't have to replace my battery box like you have to if you go to a Gel style. Please voice opinions.