I am almost certain that back then Google Authenticator didn't have any kind of export/backup (I am surprised it has now!); however, I've imported them manually.
You can now export all your codes but in an unencrypted format if I remember correctly. I am not sure what you mean by limitations for Aegis.
Can you use it on every exchange that accepts Google Authenticator, for example. Or are there certain exchanges where Aegis can't be used, and you have to use an alternative?The only thing I've missed in Aegis (and it happened only once) was the time sync Google Authenticator used to offer.
Sorry, what is the time sync 