@0x56
I would avoid Google Authenticator and Authy. GA does not have backups. Authy was bought by Twilio a while back and development stagnated. Both apps are closed-source.
I migrated from Authy to Aegis and it's much better, besides being open-source.
The biggest reason to not use Authy anymore may be that they were compromised in the same breach that recently hit LastPass:
https://www.androidpolice.com/authy-hacked-what-to-know/
@voltronic @0x56 I use Duo for work stuff, and some personal. I wish PayPal had a better option.