There's one in Oakland (near San Francisco) in the spring - "Strictly Sail" it's called, although last year it had power boats - go figure :-). They have a fair number of boats, although it's not a very big show, and it tends to be the same boats year after year with a significant number of boats being the exact same physical boats each year. Still, I've gone the last 3 years and will probably go again next year. Things in the vendor tents are OK. Never have done any of the seminars.
I don't know how it compares to other shows like the Seattle
one, so I can't comment on that.