I'm not too bothered about the actual phone but need to upgrade and am wondering what is better to photograph small children. My kids move alot and blurry pictures just seem to be the most commom picture. I want to capture the best images I can but am completely confused about the differences in the dual rear cameras and high mega pixel one. Which will have faster autofocus, and which will give better results overall.
Your existing camera may not be the issue here, and the two options you are looking at may not solve your problems. It seems you are seeing motion blur. This is related to shutter speed (the longer the shutter is open and/or the faster a child is moving, the more motion blur you will see). Try taking photographs in brighter light, ideally a sunny day. If you are using a completely automatic camera (which most phone camera apps are) it will most likely go to a faster shutter speed and you will not see motion blur. This is something quite old cameras will do just as well as modern ones. If you have a camera app with basic settings options, try choosing sports mode to get the same result.