Forget any preconceived notions that you may have of conveyor belt sushi: this is nothing like Yo Sushi or Moshi Moshi. In fact, the only thing that these all have in common is the conveyor belt.
Unlike most other like sushi places, at Kulu Kulu the sushi is freshly prepared. Not here pre-made sushi and rolls kept in the fridge for the rice to solidify. No, the rice is kept in a tub at room temperature as it should be and used as and when needed. The classics are all here (tuna, salmon, eel, squid, softshell crab etc.), as well as tempura, hand rolls and various other dishes; this is what is so great about Japanese food. Whilst so much of it is now familiar (thanks, it has to be said, in no small part to Yo and Moshi etc.), there are always wonderful looking dishes, that I have no idea what they are. The fish is beautifully fresh, in big, thick chunks. The tempura is light and again, comes out freshly cooked.
Another distinction between here and other conveyor belt places in London, is that there are a fair number of Japanese here too. Being in soho, there is also a fair collection of tourists. Etiquette in conveyor belt places is pretty simple: don't put a dish back once you've taken it off the belt and don't lean over somebody to get to the food. Perhaps they should have a note to this effect up. In French would be helpful here.
I've said before that Kurumaya is one of the better conveyor belt sushi restaurants, and I still think it is (although I think standards there have slipped recently); Kulu Kulu is, in my view, even better.