I bought the upgrade version of Family Tree Maker 2012 Deluxe. I installed it within a few minutes, and linked it to my online tree at Ancestry.com without any trouble. It allowed me to review all changes prior to the sync altering the online or local trees. I have been updating my tree both locally and online for a month now, and it syncs great. I am very happy with this product. I make changes daily to my trees and haven't had any problems.
UPDATE 9/26/2012: After using this product over the past year, I have had some difficulties with the sync feature. Occasionally my trees are unable to sync between the product and Ancestry.com. After making a backup on my hard drive, unlinking the tree and re-downloading it, the sync begins working again. It's a hassle to unlink and redownload the trees, although I still prefer having them synced to the alternative of two separate trees. Overall I am still happy with this product.