My opinion: High tax rates in Europe are the "price" of free (or very cheap) healthcare, cheap university education, and a strong social welfare net. But Californians at the high end are paying almost the same price, and missing out on most of the benefits. I don't think this is a good situation, and I don't think it's sustainable.
Taxes in the USA have a lot of loopholes for the ultra-wealthy and for large corporations. However, there's not much that "normal" salary earning employees can do to escape these high rates. This ends up putting a lot more pressure on workers to contribute economically, which seems misguided since the corporations could haul their weight more here.