I'd be more comfortable with that than with my own government, that cares what I do and how I vote, having access to facebook's data on me. The scariest part of European data sitting on US servers for Europeans is that the US will have absolutely no regulations keeping them from harvesting, slicing, and packaging every bit of it, and sending it back to Europe.

Keeping the data from being shipped out is a good step (hopefully not just focused on Facebook), but reimportation of that data is a laundering process that can render local data protections moot.