down scan or down image sonar

[roadx]

my lowrance mark 5x pro died and need to get another sonar. i think i will go with color but not sure if DS or DI is worth getting?

what is the real world maximum depth ds or di will work in salt water?

will 455khz or 800 khz do the job in LJ up to 300' feet?

does anyone have screen captures or recordings in deep water using DS or DI ?

anyone have a humminbird and wants to share their likes and dislikes?

im particularly looking at the HB 597ci hd di is this a good unit ? or go back with lowrance? say elite 5x or hds 5 and forget the down scan/down image.