www.landfallnavigation.com
I like it for the simplicity. It does quite a bit but I just use the GPS map/chart It gives Lat, Lon. and heading. The only electronics I have on Roxanne are a phone/tablet, depth gauge and a radio. I have paper charts for southern California but those don't help when it's hazy and you can see neither the mainland nor Catalina. I wouldn't recommend it as a primary nav/chart plotter but In a pinch it will tell you exactly where you are.
Take a look at the Navionics app. It works very well on an iPhone. There's a 2-week free trial with full features, so it's worth looking into.
Have you ever looked at Navionics? How does it compare to iSailor?
OK, this is another one of those "depends on how you use it" questions. I like iNavx because I can select the chart I want to use and not have it chosen for me. Most often in coastal sailing I probably will want to see multiple charts in different scale when planning--I want easy access to all of them and to know what scale I am on when I am looking at them. I generally carry every electronic chart available for any place I go. This saved my bacon more than once on deliveries when I had to find a hidey hole from crummy weather--having very detailed electronic charts to look at is a good thing. I still carry paper for very high level planning and guest amusement, but you probably know that they are not going to be made in the future. I also like iNavx as it seems dead simple to set courses and I like the display sense. iNavx still has some NOAA raster charts available (so sad they will no longer be produced) and I think the vector charts of most other systems are ugly and harder to interpret---they were designed to accommodate the limited chip and memory specs of the first chart plotters . I still have a hand bearing compass and plotting tools but have not touched them in 15 years. Have a sextant for sale in excellent condition.
+1.