If shooting speed is critical it would pay to do some research before purchase. There are digitals that are capable of two to three shots per second. On the other hand, some cameras take as much as three to seven seconds between shots. You might be able to speed this process up. By pressing the shutter release button half way down some cameras will figure out the focus and lock it in and then use it for the next image.
Half depressing the shutter release can also lock the exposure settings as well.
Some cameras have a very slow auto focus system and using manual focus relieves the camera form dealing with that function. If the camera does not have to display the image after it has been captured it might be able to get on with its next task more efficiently. If you camera has the ability to use an external flash then get one. Some of the better flash units are capable of firing at least once per second. With the camera s internal flash turned off, the camera has one less thing to do, and your batteries will last longer.