Depending on what you're shooting and how you're doing it, you probably won't notice any difference in the fastest of the bunch here. DSLR's send the image first to a buffer that can hold several (or more) images and then write them to the card - you don't have to wait to take another shot unless the buffer fills up. I've never had that happen personally (unless I was trying it out to see how it worked) but some sports photographers look for the fastest system they can get.