I think San Francisco’s Japantown is worth it only if you have never been to a Japanese-American community like that before. There are 3 major ones in California (Little Tokyo in Los Angeles and Japantown in San Jose) and as a Japanese-American, I say without reservation that they all suck but it’s what we’ve got so we must work with it to make it better. They are all quite small (as compared to other ethnic ghettos) and are not as vibrant as they once were (very sad to walk around and see all the vacant storefronts). The SF and LA ones are the only ones worth bothering about. What is great about these communities is that in a compact area one can absorb Japanese culture, whatever your background may be. The food at restaurants, books/music at bookstores, pop culture at anime/toy shops, etc. What I personally like about SF’s Japantown is that it is in San Francisco, of course! The mood is nicer than LA and since it is more compact, easier to see the whole. I have only been to a festival in Japantown once so I cannot really comment on that aspect of the community.