It's basically a matter of taste. I do prefer sashimi, because you get the full taste of the fish. In sushis, you have a little bit of wazabi (that is mustard), and it somehow affects the taste.. I would say that sushis are for people who try japanese food for the first time. It's not 100% raw fish, so easier to get accustomed to.. Hope this helps!. Love and kisses from Paris, France