I bought Hummingbird units when I ordered my new boat in 2016. Side scan at the console, down scan at the bow. I am not unhappy with the side scan, but there is a learning curve. I spend most of my time fishing piles and spots that I already know. I know if I had to do it all over, I would have to think real hard about the the need for side scan. When I do go graphing, I find I use down scan more than side, as I am graphing points, humps etc. This probably wasn't much help, but just another's experience.
Don