kids, family and motocross.

Well, there is no single way that I can recommend sony over nikon. some important features of nikon are: robust image sensor providing you with better image quality and covering wider dynamic range. Also D7000 provides you with a lot of buttons and knobs so you can easily and effectively change your camera settings. About the bikes and capturing perfect moment I should say it doesnt have anything to do with the camera because most of these new cameras have almost zero shutter lag and as soon as you trigger the shutter button you're gonna get the picture. But when it comes to low light situations then the camera is forced to either increase the iso which results in noisy pictures or increase exposure time which results blurry pictures. So if you think you are going to shoot in low light (like a bike competition or something similar) then you should invest in getting a good lens instead of being worried about the camera. good luck