I know someone whose 2-factor phone authentication was hacked... 
I use the Google Authenticator app, which makes the token only available to that specific device, rather than through SMS. This gets around the problem of cloning a phone number.<p>iOS: <a href="http://itunes.apple.com/us/app/google-authenticator/id388497605?mt=8" rel="nofollow">http://itunes.apple.com/us/app/google-authenticator/id388497...</a><p>Android: <a href="https://play.google.com/store/apps/details?id=com.google.android.apps.authenticator2&hl=en" rel="nofollow">https://play.google.com/store/apps/details?id=com.google.and...</a>