Income taxes BC <> CA are pretty similar, but other taxes aren't. Gas is the equivalent of $6/gal in Canada right now (due to taxes), sales tax is 12% and a lot of products (electronics, etc) are just generally more expensive in Canada.
This is something I've been comparing. I'd pay a little less in income tax in California actually for my brackets, but even though rents etc in SV are higher, I also would be paying less for gas, groceries and any entertainment and tech purchases.