So there is going to be a huge problem for people choosing iPhone 6s in 16GB. That problem is 4K video recording. Apple announced this amazing new feature for the 6s. The inherent problem with this upgrade is that the video size is going to increase dramatically. Currently with my iPhone 6, one hour of 1080p video takes up 10.1GB. Luckily most of us are not taking 1hour of video at a time, but all the little video clips add up quickly. This already means that the 16GB model did not leave much space for anything else when your taking video. Now lets talk 4k Video. 4K is four times the resolution of 1080p. This means that file size is going to be gigantic even with the h.265 compression. For example Tears of the Sun, a 4K short filmed at 23 FPS (7 less that what the iPhone will shoot) is only 12minutes. The file size 11.9GB. That's about 1GB per minute. So after the 16GB format and ISO install you left with about 14GB giving you only 14min of Video space if you install nothing else on the phone. Please take this into consideration if you are getting the 6s.