The only downside is that it takes a few minutes to get the ADS weather after takeoff and the "flyover states" have limited coverage.
Also it only downloads weather a few hundred miles around the airplane so you won't get destination weather until you are around an hour from landing.
If you are using ship's wifi for other aviation sites it is a bit tricky disconnecting from the ship's network and connecting with stratus and vice versa as you change applications.
It's a really good system with no subscription costs. The GPS is WAY better than any of the bluetooth GPS receivers on the market. if I had my own airplane I would definitely own one.