G'day,
I guess im still in the learning phase with my garmin unit and the g2 visions charts capabilities and im not sure what your base map looks like but if u dont have the fishing charts on it id say the g2 vision is worth the money for that alone, the same with say having to buy a navionics chart to put in a lowrance unit its well worth the chart info.
As a side note ive found split screen between the navigation and mariners eye views to be handy when navigating in areas that i have not been before.
Cheers
Bandit