Hello, I am an engineer. I use MacBook Pro Retina 15" (Windows via bootcamp for Windows app and Mac OS for normal use such as writing papers). I have a Galaxy Note PRO 12.2 which is also my cell phone. My Note PRO 12.2 malfunction often. As I am in Japan, they don't fix it since it is not available in that country. I am considering buy buy an iPad PRO with cellular phone functions and/or Note 5 and/or iPhone 6S Plus. I use the S pen on my Note PRO often to write notes and do annotations. I also take lots of photos/videos. So, excellent battery life is highly desired. Note 5 is a good choice but no support in Japan. iPhone 6S Plus would be the next choice but it does not has good 3rd party stylus. I was waiting for the Surface PRO 4 with cellular phone function but Microsoft decided not to include this function. I use Mac OS for general purpose use and academic paper writing. I use Windows for 3D engineering applications and CAD. What suggestion do you have? If possible, excellent battery life, light weight, excellent stylus support for hand writing and annotation. I guess a Surface PRO 4/book which can run MacOS with cellular phone function is the best. Unfortunately, it does not exist. What suggestion do you have?