I have a 987cx side scan very good in shallow water upto about 30m and ok to 50m in sidescan mode. Very good in std mode. Latest updates to software and humminbird pc make it a great combination. Read the humminbird web forums or look at some of the US treasure hunting sites for more info. It is possible to record .son video files to playback later.
Use as chartplotter is comparable with Garmin or Raymarine but mine does not have alpha numeric keypad so scrolling through over 200 waypoints takes time but is not unreasonable.