I am considering dumping my iPhone 5 and going with an iPad Mini 4G LTE. The fact that I use more data than voice calling and the 10 hour battery life on the Mini make it very appealing to me. I might use a dumb phone on the side or I may just use the iPad Mini for voip calls also. How do I figure out how data voip calls would use? That would be the determining factor. I would use google voice or skype.