I used a Humminbird Helix 7 DI/SI/GPS all last year. I really like the side scan. You can see downed trees, logs, other structure and even fish out to however far you set the range. Yea, just like anything else, you have to figure out what is what, but once you are comfortable with it, it really helps. Last year, I was on Tully Lake paddling along and saw on the SI what I thought was a fish echo beside a submerged log in 14 feet of water. I set a waypoint on the GPS. Marking the spot tells you what bearing and how far away that spot is. Got my kayak oriented toward the fish, cast out past the fish, left the lure sink and dragged it past the fish - he bit it, I set the hook and fought the fish. He spit the hook before I got him back to the boat, but the experience using SI and having positive results like that really gave me more confidence to use it a lot more. I think the extra money for SI over just a unit with DI is well worth it and adding GPS is even more worth it. Save up and get all that you can, or you'll be wishing you did after you didn't.