I have caught a lot of really big bass this year and not a single one came from an image from my SI or DI. ...I have two of them, one up front and one on the console. Wish I had that money back to spend on a better TM.

Sonar and GPS, OTH, I use everyday all day.

People who say you don't need it, probably don't understand how to use it to it's full capability, or do not understand it's true purpose. You're not going to see more fish with SI, but what you're going to do is find better fishing spots. Example: summer fishing we are out deep fishing points and humps, but with SI I can find a rock pile, brush pile, shell bed, etc faster and more efficiently. Bass don't randomly hang out in deep water, they're at those spots for a reason, and prefer some type of cover. This is a just an example as there are many uses for SI, but again I will say it will not help you see more fish.