…through a third-party cloud server that you have no good reason to trust. No bueno. Keep sensitive information off the cloud unless you want it to become public.

This! Authy is very very nice. Syncing accounts is a life saver, both as backup, and not having to pick up the phone all the time.
Cut and pasting with a click instead of reading and typing, is so much faster.
Easily search the very long list of entries.
Not open source tho, but free as in beer.
If Aegis had the sync option, i would have used that. But it did not last time i checked.