I've eaten Sushi all over the US and a few cities in Europe. I am in no way an authority on it, but I know what is good. At least in my world. So on a recent trip to Berlin, I was really surprised at the quality of Sushi. Particularly at one restaurant that was recommend to me.

Kuchi located on Kantstrasse 30 in West Berlin is a great place for good, not super expensive sushi. The waitstaff is quick, really nice and helpful when you need to make a decision on food.
The joke with Sushi is that no matter how much you eat, you'll be hungry an hour later. At Kuchi I found that not to be the case. The amount of food was generous and filling. Between three of us we managed to polish off soup, appetizers and three gigantic rolls before calling it a night.
One thing I appreciated was that they had English menus and were happy to speak English with us as opposed to a few other places that we ate at in Berlin. I try to speak the language in what every country I happen to be, but it's nice to know exactly what you're ordering, especially with fish.
I would recommend Kuchi to anyone hankering for some Dragon rolls on your next visit to Berlin