I’ve been using Google Sync for quite some time, previously on my Nokia handset, then tried it on the iPhone 3 and now on the BlackBerry 8900 for the last 1.5 years. In all, that would be a good 3 years of syncing my contacts on the go with my Gmail account.
So no matter if I lose the phone, wipe the phone or upgrade the OS, or even change the handset, in 10 minutes I have all my contacts right back where I want them, along with my saved Calendar events on my Google Calendar. I’ve added a few screenshots below to show you simple the operation is, this one being for any of the BlackBerry handsets. The process and approach is equally simple for the iPhone and especially on Android handsets, since they get you to start off with your Google ID.
The images are self explanatory. Once you start using it, you won’t go back on it. Once you update your contacts either on Gmail or on your phone, it syncs automatically in a while. The default schedule is set for every hour I believe. The best thing in my opinion is that you don’t need to fiddle around looking for email addresses and then linking them up to numbers in 2 or more different locations.