[jeff k]

Two ways to export mail contacts, one export, get a .abbu file

Other is select all and export all v cards. Both were shown to me by an Apple tech.

Do these both work equally if you need to bring them all back into Mail?

[andi*pandi]

Assuming you mean Address Book? then I would stick with the .abbu file. If you were converting to some other utility, the vcard might be more compatible.

[jeff k]

Andi, it's called Contacts for a few years now, no longer Address book. That said your answer still holds?