The two systems are quite independent of each other, which is why the Android version is currently some way behind the iPad version. From what I gather, the Android system will develop quite quickly to offer similar functionality and perhaps more than the iPad version.
I have both, with an iPad mini and a 7" Samsung. The samsung offers what I call a 'lite' experience compared to the iPad. Disregarding all the white noise about viewing size, the mini is a very adequate platform for knee board use or for crowded cockpits. Although if I had the choice and space, I'd mount a full iPad either on a RAM mount or fixed to the panel.