I sync my Google contacts with my iPhone using iOS’ support for Google Sync (aka Exchange ActiveSync).
It works fairly well and lets me keep my phone up to date automatically. The only major problem is that it doesn’t support certain fields like “Profile URL” (ActiveSync mislabels it “Home Page”) or it runs into problems with telephone labels like “iPhone”:
Last week, Google released support for the open contacts synchronization standard, CardDAV. And, so far, Google’s CardDAV support seems to be much better, as it’s not limited by the underlying ActiveSync field labels. Also, according to my completely unscientific trials, CardDAV appears to synchronize a bit faster.
Google CardDAV doesn’t yet work with Google Apps for Business, so we business users will need to be patient and sign up for a FullContact beta invite. But if you’re a GMail user, go ahead and try it out! Just like ActiveSync, it will only synchronize your contacts with the “My Contacts” label – but either way, it should make it even easier to sync your Google Contacts to your iPhone.
(And if you’re looking for an easy way to sync Google Contacts across accounts – sign up for our Address Book beta!)