Poor Backup Options
I have used Google Authenticator and Authy. Initially I preferred GA due to less txt alerts. But real test was transferring to a replacement phone. Apple replaced my phone, did a restore from icloud and wiped old phone. Authy was easy to reauthenticate and kept all sites linked. GA did not. All was lost. Kept walking me through resetting my Google 2-step but no way to get previous sites entered.
Tmittleman about
Google Authenticator, v3.0.0