I experimented with 3: "Adddress Book to CSV Exporter", "Address Book Exporter", and a shareware "Export Address Book 1.5". The shareware costs $12.

Between the two freeware, "Adddress Book to CSV Exporter", is by far the best. The test seemed to me to be complex entries, with multple phone numbers and email addresses,notes, and custom fields. The older (2002) "Address Book Exporter" never got it right and dropped all kinds of information.

"Adddress Book to CSV Exporter" performed flawlessly on a Gmail import. I could find nothing that it lost. Excellent software, free or otherwise.

And... as if that were not enough... it even has a Klingon mode. Boy, i bet Antonio Lore is a fun date.