Hello, anybody using iPhone 6S+ to provide non-stop internet access for Ipad Pro? Any advantages/disadvantages doing that? If I want to do it this way, shall I get the wifi or wifi+cellular version of IPP? SP4 or Surface Book seem to be more useful than the IPP. However, I read that their battery life is very bad. I read that about 4 hours for SP4 and 2.5 hours for SB. IPP is about 9 hours.