I have spent time in Tokyo, Misawa, and Osaka and ate an awful lot of sushi. Most sushi restaurants here in the US with a real sushi chef (not an all you can eat chinese buffet that makes sushi) are close enough. About the biggest difference is that they use real wasabi in Japan instead of dyed horseradish paste and they have more esoteric options (unless you really like sea urchin or whale or bluefin tuna fat [yes just the fat]).