I have now got most of the east coast blue maps in my computer and i can tell you its great. I can enter gps marks, set out trips/routes on the pc and down load it to the gps unit.
In general its just handy to have the maps to look at and see your fishing spots/areas and even look at depth changes in certain areas which may contain fishing grounds/reef
Heres one of a few maps that do the fraser area. I can also put my pointer anywhere on the map and it gives me exact gps marks for that spot. I can also zoom up the map to an 80ft radius to look at spots really closely.
# # # # # # # # # # # # Cheers Greg