The resolution and size of the phones depend upon how you use it. If you use your phone to edit images, videos and would like to watch movies then it is preferable to go with 6 inches or more. If you would rather use it for occasional browsing and videos, you can do with a 4.5 inch screen too. iPhones, for instance, have a 4.7 inch screen. If you require something more from your iPhone, you could go with the Plus version. Samsung's Galaxy Note series is for those who love the bigger screens while the Samsung S series is for those who can do without it.
