I just returned from a 10 days bareboat in the BVI and used the Navionics charts on my iPad pretty extensively. Great for planning and I do like the interface more than the Garmin that the boat came with. It was just my wife and I on the boat, so being able to bring the tablet over to each helm and not futz with the fixed Garmin was nice. Always glare on those dirty screens (no matter how often you clean).

No issues with updates, its the same one I bought for a charter last year and I didn't notice any errors other than some minor stuff (Sprat Bay on Peter is deeper than they mark). I did hear through the grapevine to be careful around the last channel marker entering the harbor at Anegada as some sands have shifted, but did not have any issues with a boat drawing 6ft.

I use an older iPad for it that I wouldn't lose a bunch of sleep over it if lost, but haven't had any issues over 2 years of charters.