I ran both Navionics and Lakemaster like Navionics I think has better contours and Lakemaster you can highlight all different depth ranges you want to fish both are good though me personally I would get both.
I have the Lakemaster on my bird. It works well. I have never used Navionics but others that have seem to like it. I think at some point they will all let you down at a time when you need it most(Murphy's Law)but I have no issues with Lakemaster.