[jenscow]

That's a feature of most "cloud" services that allow multi-device synchronisation.

It could be said Google already have your browsing history (of sites that they serve adverts on, or that use their analytics). I doubt Chrome's syncing data would give them any more information than what they have already.

[phaer]

Firefox provides synchronization without relying on 3rd-party servers, you can just use your own or one provided by a trusted friend.

and it's quite easy to block Google from tracking your browsing habits using GA or Ads: just use an Adblocker and something like Ghostery, RequestPolicy or Disconnect to block Google Analytics.