I've been a happy customer for several years now. I've had zero problems with them, but I also don't use the web interface for anything other than managing my accounts (one feature is you can easily setup and manage family members accounts).

I don't think that moving outside the US would make any practical difference. Any mail sent to their servers from my regular correspondents would pass through NSA monitored sites as they left the US and I pull everything off using IMAP over SSL anyway so there isn't anything stored there for them to seize.

Your email correspondence, unless encrypted with pgp, really should be considered no different than sending a postcard in the mail. It can be intercepted and copied at any number of points along the way.