We first used the Ipad in 2011, few local trips to get used to it, then off to OSH. It was running SkyCharts Pro at the time. Great program, simple and easy to use---- but it seems to have gone the way of the Dodo

We also used the Ipad to run weather, and AirNav for route planning to get the fuel stops optimized.
Later switched to Garmin Pilot when SkyCharts stopped updating their charts. Hated Garmin Pilot---------does way too much, thus way harder to figure out how to use---------IMHO, decidedly not user friendly.
We now have ForeFlight----------I see it as kind of a blend between the previous two as both in function, and ease of use.
Our plane has a panel mounted AvMap gps, and the GRT EFIS also has internal GPS---------and then there is also the Ipad-----all three always show a very close if not identical position. This is without using an external antenna for the Ipad. I keep the GRT set to a 30 mile range, the AvMap set to 90--100 mile range, and the I pad whatever seems best at the moment.
The big advantage of the Ipad for us it the ability to zoom in/out rapidly, and to search other stuff along the planned route. Also, we have a Stratus 2, so the Ipad gets the weather and traffic.
Is it needed-------------no.
Is it nice to have---------very much so, would not leave home without it.