An iPad is not built to be used in the way we would use it, for hours on end with a large app running. So not all navigation devices are equal. There is a reason certified hardware costs so much more.
I have had the iPad go wrong several times.
I found a bug in OzRunways that the developers hadn't found yet. It's not fool proof. But I am a lot more reliable as I know myself and what I can do, and I plan and look at a map and have a great time planning, and I really get a good feeling when it all comes together and I arrive where I should be, using paper. It just doesn't feel like such an achievement using the iPad.
Are we flying, grass roots style, or are we looking at electronic toys?