Had downview on a humminbird for quite a while and only really found it 100% worth using when I wanted to identify a type of structure on flat water. For everything else (fish schools, predatory fish, etc.), I never struggled with standard sonar. Striker 4 has been a good little unit for me though- quality picture and the mapping is great. Only gripes are that the plugs come out a bit too easily and the zoom function for the map needs quite a bit of accuracy with the small buttons.
I caught a cobia which could eat the rest