Works well, but only in (cheap) paid mode.

You can test this app with 40 contacts, but in order to do the heavy lifting you need to pay. That said, it is definitly worth its € 3,99, because it is indeed fast, and seems to work correctly, which cannot be said of all sync apps around. It also has the option to sync only certain contact group, which is great if you keep all your contacts, but don’t want them all on your phone or gmail account. Ah, yes, and the German translation is *completeley* obscure, so better switch to English if you can figure out from the „german“ interface :-)

opfeifer about Contacts Sync for Google Gmail, v5.1.2