The sync that Google offers for Google Contacts <> Mac OS X Address Book is seriously flawed. It doesn't sync automatically, it doesn't sync all contacts, it doesn't sync all fields. See here for a list of warnings and issues.

Is there a better way to sync Google Contacts to Mac Address Book bidirectionally? Preferably free, and preferably without adding extra software.

I have tried to do it through Plaxo (which has an excellent Mac Address Book sync, albeit through an extra software install), but Plaxo doesn't handle Google Sync well (no updates).

UPDATE: For the new Mac OS X Snow Leopard this shouldn't be an issue. This question is looking for a Leopard answer.