I must say that I am a recent PPL and there was very little to cover the use of GPS and apps such as skydemon, but I wish there was. I use skydemon all the time now. I haven't to this point, but when I come across an aircraft with a built in GPS I am going to be left to my own devices to work out how to use it.
If the technology is there, it should be used. And I now use skydemon as my main nav tool. I always mark up a map and have a paper PLOG, handy for scribbling clearances etc (although I don't bother with the timings, but would if SD crashed and I went back to the map). This serves me perfectly. Why on earth this isn't the standard way of going about a XC is beyond me.
*Ducks for cover*