This is, hands down, my FAVORITE app. There are others that I use more often, but only because were only out on the boat now and then, and only in the summer (this being Alaska, winter is NOT conducive to boating). I think that it is fantastic that I can track our progress from the passenger side (or anywhere else) and make sure my husband is aware of any possible obstacles that I see on the chart, that may, or may not, be showing up on the main GPS. The only improvement I would like is the tracking line. Its kind of hit-or-miss. Some times is shows, sometimes it doesnt. No biggie, but it would be nice if it were more consistent.