If you are looking for a causal Japanese/Sushi place I would highly recommend you try out @Chez Sushi. My friends and I loved the chilled out environment. You feel like you are in Tokyo instead of Dubai. They also sell sushi related merchandise which is too hard to resist. Their rock is to die for and beats PF Changs dynamite shrimp to some extent. I also love how you can customize your own sushi too.