I've used it for about 3 years now. iNavionics for the Carib Panama area SUCKED. But the Aisia / Africa area so far has been spot on. Galapagos and the Panama Perlas was also spot on. However there is a new app SEAiq that you can use all the OpenCPN charts in that I'm most likely going to get and appears to have more functionality. IMHO worth a gander.

When we crossed from the Galapagos to the Marqueses the ipad was used for most of the trip. It's current draw is minimal and I only turned on other computers when I downloaded GRIBs or Current Data. Didn't even need to run AIS. Hell; we saw only 1 ship in 19 days. A vast ocean with not much traffic.

I'm damn glad Apple is a good strong company, I would hate for one of the sailing Nav companies to buy it out and ruin a reasonable priced multi use tool on the boat. It is always nice onboard when any item can be used for multiple task.

As for out in the cockpit. We've only had it out side a couple of times. Have a waterproof vacuum bag and a suction cup pump that we can attach the ipad where ever it is best to use. For most of it's life it just stays below.

Go Slow
Sail Far
Stay Long (except in French Polynesia where they don't want you for any length of time)