iPads are almost universally used in the US, but overheating and attendant unexpected shutdowns a are a nuisance. There are large, clunky devices with fans on the back available to try and mitigate this. In the UK, many people prefer to use an Android tablet, either 7" or 8", dedicated to the job. Very cheap by comparison, battery life is 400 miles plus, the GPS receiver generally doesn't need another device. My android tablet gets an excellent signal on my knee. Panel mount if you have room. Skydemon is very good now. It's a legal requirement to carry a current chart, but whether or not it has to be paper is a grey area.
A massive iPad on a sucker on the window not only obstructs the view out, but could be a liability in an accident. If you yoke-mount, make sure it doesn't obstruct the view of the instruments. The wires you need to keep it charged will also get in the way in an emergency evacuation.
Just my view, based on experience flying with other people with iPads and my own xcountry flying.
TOO.