I went iPhone4 -> Galaxy Note II -> Moto X.
I still have a ton of paid for apps and games under my iTunes account that I share across with my iPad. I've also got two OSX machines in my home.
My primary office is a cellular black hole. I get zero reception so SMS and calls to my phone are almost always delayed. Going back to iOS gives me at least integrated iMessage so I can still text my wife and a couple friends easily over wifi. And with built in wifi calling I might actually be able to make phone calls too
And given my cellular black hole, if my phone isn't on a charger my battery can be torched by 11:00AM as phones try and search for signals. The beefier battery in the Plus is appealing in that regard.