Probably doesn't belong here, but since it involves maintenance of my Grady, here goes. Any of our readers have a strong preference for either? Both are pricey, but I know both brands represent quality. Have probably owned more Yamaha products than other brands, including home electronics, and I really trust them. I need something to charge my batteries in case the maintenance people at my marina turn off the power to the outlets. Recommendations on where to buy? Thanks.