Rickie hit it on the head, I like the water column to show for a couple of reasons. At a glance I can tell what the bottom is doing and this really helps in the skinny water. yes I can just use depth reading at that spot but having the trail is just something I prefer better. Also I like it in deeper water due to the information it gives you on whats under the boat when it comes to fish in the water column and or structure.

I started with a DI unit but with the cone it shoots you have to cover a lot of water to get an idea of what's in the area not to mention in shallow water you have to run over or very close to check it out. (spooking the fish). SI covering 75-100, 1 or 2 passes and I know what's there and if I want to take a better look at something. I mark them with a waypoint, bring in the view and re-scan to see if it's worth dropping a jig.

Don't get me wrong. DI units are great and will put you on fish with some very detailed images. Just ask yourself what you need and how you like to fish. good luck