..SNIP... Greenaddress.it all uses central validation. I don't particularly trust biometric authentication. After all, people have exploited iPhone's fingerprint sensor and people can knock you out to steal your Bitcoins.
Actually with GreenAddress you have the option to validate via SPV on GreenBits (on by default) and via Electrum servers on the Chrome or Cordova apps (on by default). With GreenBits you can even connect to your own node, including via Tor Onion bitcoin nodes