I use the igills as a backup computer. It is a simple system that is very reliable. I tend to use the video and camera function to capture things quickly and it works. I have used the light function and it works but I wouldn’t use it as a backup. The compass feature is very good. I dive with an OC1 and absolutely prefer the compass of the igills in comparison. Lastly, when all done with the days dive, everything is nicely logged for you. Max Depth, Average Depth, water temperature, air mixture, long/lat coordinates, photos & videos, depth graphs, Down time. It is a viable computer and if in worst case scenario you need emergency assistance when on the surface, you’ve got a phone.