So I have been using my pearl 8100 for a few years now and it's I think it's time for an upgrade . I have been looking at either the 9900 or 9790 bold. I love how small these devices are, that they fit perfectly in my hand . My question is, what is the major difference between the two besides the screen size and processor? I have also read that the 9790 has an auto focus camera. How is the battery life on both devices? I have read that it's not very good but has improved since OS 7.1 came out? I don't much care for media like music and video since I have a mp3 player and PlayBook for that