Here are my thoughts on the Elite 4 DSI. Reply that turned into a review, so forgive the hopping around.
Had it out for 10 or so trips and its got its greats and 1 horrible. It can generate some pretty impressive returns in deeper water. On the shallows, < 3ft, it gets a bit cloudy, but the depth readings are always accurate. Maybe all the way down to < 1ft.
1 thing I really don't like about it, is the sd card slot. Its suppose to be sealed by a rubber gasket. But the rubber gasket doesn't like to stay put. So saltwater can and will enter the slot causing rust to form on the pins where the sd card goes and malfunction. We'll see what Lowrance does about this problem and report back.
Other than that, its a great unit. The gps is quick and accurate. Lots of functions that we'll probably never use on the kayak and lots we will. Marking spots, scrolling back through the sonar page and mark some fish. Switch back to the gps page and navigate to it. Awesome. Tracking back your course in fog or low light. Never be lost again.
Installation is can be straight forward or creative, depending on what you want.
Most of these images are in some of my recent reports.
Rig offshore, with coral growth on the legs.
Same trip, but here we see a bait ball being chased to the surface by a few bigger guys.
same bait ball.
Long fish cruising the bottom.
Now for some shots from the causeway.
Bait ball sitting just off the battleship.
Can you see it? Crab trap.
Another. Notice where the buoy line is, the tide was ripping out that day.