I don't know the Bluechart app.. but I just downloaded the latest app to support ActiveCaptain called Skipper, and it's REALLY impressive at first glance. I learned about it from today's ActiveCaptain newsletter. It includes weather overlays from Weather Underground, auto-updated NOAA marine charts (or Google Earth or Topo maps, selectable), and ActiveCaptain data content. All is cached and displayed offline very seamlessly, except weather and Google Earth requires an online connection. It also does routes/waypoints and real-time navigation (which Garmin's app doesn't do) with real-time stats that can be captured. It's $12/year for the Pro version and you don't have to pay extra for the charts you've already paid for in your taxes. Your subscription syncs your personal data and routes/waypoints/tracks etc. between your multiple devices (eg. iPhone and iPad) for the one subscription fee.

As for the ActiveCaptain content -- it does have some marina facility and harbor data that is baseline, but many of the marks are user-created and all of the reviews are crowd-sourced by users like you and me. The more reviews for a particular mark, the easier it is to spot the aberrant ones and more reliable picture comes through as you scan the reviews. If many people say similar things you can probably rely on it. Certainly it's more reliable than reviews by cruising guides that accept advertisements, and AC data is more up to date also. I'm a big user of AC data and try to contribute as much as possible. (I have over 600 contributor points so far)

I haven't used Skipper on the water yet, but I'm very impressed and suspect this is the app I've been waiting for. If the weather cooperates I might use it this evening.