To the OP's initial question, an Ipad is especially useful if the only chartplotter is at the helm as it allows someone other than the helmman to help with navigation.
Typically the helmsman needs to adjust the zoom on the chartplotter for steering duties - instruments, AIS, radar, course, route, nearby buoys and hazards. Having someone panning or zooming the chartplotter is distracting if not dangerous.
Our Ipad lives below on the chart table were navigation is supposed to happen. No need for a case as it is dry. I picked Garmin Blue Chart a few years ago because my wife found it quite intuitive. I thought it did the best job at the time of ActiveCaptain display (fast, background update, good fonts, etc).
I ignore the Garmin update reminder as I see no reason to update the charts very often as it is not the primary navigation system -- and postings on ActiveCaptain would likely tell you of a change quicker than any chart company update.