Xmarks for Windows 8 is the bookmarking and open tab add-on. Keep your bookmarks and open tabs backed up and synchronized, across computers and browsers. You can sync bookmarks with your other browsers and devices,snap Xmarks to the side of the screen, and have your bookmarks available while you browse, add bookmarks from Internet Explorer or other apps by using the Share charm, search your bookmarks with the Search charm and type-to-search support, and open tabs from another browser or computer
The specs and product webpage say it will synch both your bookmarks AND your tabs. In fact it seems to do so on installation. HOWEVER it does NOT recover your tabs. So if you trust this product you will lose all your tabs and months/years of work!!!!
In addition they have no customer service whatsoever. They have not returned my email in a week and their forum is a desert - nobody responds to questions!