They are all easy to set up and operate provided that you don't want to do much with them. Out of the box, they all surf the web, they all have Wi-Fi, they all do email and and SMS. On Page Plus, you will want to turn off the phone data, which is easy, and only turn it on if you are lost and want the map, or receive an urgent email or something.
As far as I can tell, none of the smart phones have as good signal reception as a good flip phone. Setup is pretty easy on an android phone, although you will need a gmail account as well as the others -- doesn't mean you have to use it, just that you have it.
The complexities begin when you want to do more with it.