Contact sync between Google Apps, Gmail, and Mac

I am trying to find a way to keep my address book in sync across my:

• iPad

• MacBook Air

• MacBook Pro

• iMac

• Google Apps account

• Gmail account

as well as my wife's

• iPhone

• MacBook

• Google Apps account

• Gmail account

(Aside: by "Gmail account" I mean a regular Google account, as opposed to a "Google Apps" account. Most people interact with it through their Gmail so I'll use "Gmail account" to differentiate between "Google Apps" and "Regular Google" contacts.)

Would you believe that the hardest part is syncing between Google Apps and Gmail accounts? Even if the accounts are linked via multiple sign-in, I can't find any way to keep their address books in sync. You might think Google would make this easy, considering that I am trying to sync between their own products.

First up: Plaxo

My first concerted effort to keep these in sync was to try the most expensive solution: Plaxo. Plaxo started several years ago as an online address book. They went through a dark period where they were best known for auto-spamming everyone in your address book, and then they tried to become a social network. Recently they have renewed their focus on address book syncing, and have amended their previously "overzealous" notification system.

For $60/year, Plaxo offers a Platinum Sync option which is supposed to be able to keep just about anything in sync: Outlook, Gmail (including multiple accounts), Google Apps (including multiple accounts), iPhones, BlackBerry, Mac Address Book, and Windows Mobile.

Platinum sync is described as:

Although Plaxo is expensive, I decided to use the free trial period. If it worked and saved me the time that I would have spent hunting down another solution, perhaps it would be worth the price.

I set it last week, starting with the Google Apps and Gmail accounts with the premise that those were "always on" and the part of my previous sync setup that I had not been able to solve otherwise. I added 4 accounts (two Google Apps and two Gmail) accounts, and just one Mac. I let everything sync, and then went through and fixed problems, merged duplicate contacts, and so forth.

Then I just let it run for a couple of days to see how it would work.

I checked this morning and it showed that my Google and Gmail accounts all sync'd several hours ago (I had been asleep all night, so nothing had changed). It had been more than seven hours since the last change. So how did Plaxo do?

The good news is that my Gmail account and my wife's Gmail account appear to be in perfect sync, both showing 1,851 people listed in "My Contacts." Unfortunately that is the end of the good news.

Her Google Apps account has 1,853 people listed in "My Contacts." My Google Apps account has 2,759 people listed in "My Contacts." And my MacBook Air has 2,110 contacts.

My Plaxo account shows I have 1,853 contacts.

That means that Plaxo has only kept one out of five accounts in sync with itself. That is a drastic failure.

If you think that it's not that bad because two of the other accounts were only off by two (1,851 vs 1,853) let me ask you this: which two contacts are missing? The answer is: I don't have any idea. But if it can't manage to keep 4 Google/Gmail accounts in sync and failed to even raise an alarm that something went drastically wrong with one of them (2,759 vs 1,853?!?!) how am I supposed to trust it?

If Plaxo had sent me a message saying "We noticed that your accounts [X] and [Y] were not in sync, even though no errors were reported during sync" I would have at least trusted that if something went wrong in the future I could count on Plaxo letting me know. Failing to sync is bad, but failing quietly is much worse.

No solution, still looking.

I haven't found a solution yet, and am hoping that perhaps one of TUAW's readers might have an idea.

The crux of the problem is being able to sync one Mac to two Google accounts (one "Google Apps" and one "Gmail"). If I can find a reliable way to do that I will replicate the setup on all of my Macs, and sync my iPad and my wife's iPhone using Google's implementation of ActiveSync.

Has anyone else cracked this nut? If so, let me know in the comments! Meanwhile, I'm already trying out another solution. I'll let you know how that one goes.