I have a Lowrance HDS with side scan and I find it only marginally useful on Erie. Part of it is I'm not confident in interpreting what I see. I'm completely confident in the regular sonar. In theory I should be able to identify fish off to the sides while trolling but since I seldom use it I'm not too good with it. The second reason is I don't spend a lot of time structure fishing in Erie. Maybe in the spring around the reefs. Maybe a little while smallmouth fishing. I do use it more on inland lakes. However giving it to do over I would still buy the side scan feature.