I have a Humminbird Helix 9 Mega unit and am trying to figure out what mapping chip to get. I know that the Lakemaster is specific to Humminbird, but does that mean it's better? I've looked at the list of lakes/rivers that the Lakemaster chip would have for my area, and all of the places I fish have HD maps. But the chip for my area is also a 2015 version and I know that you can update Navionics chips whereas you can't with the Lakemaster. If anyone has used both chips, can you give me the advantages of each? Disadvantages? Thanks!