If you are just needing to sync 1 set of bookmarks across multiple machines there are other options then the dedicated bookmark sync add ons. You are probably using one of them already!
Options to sync book marks across multiple machines(Just a few examples):
1. Drop Box
2. Sugar Sync
3. XDrive
4. ADrive
5. Sky Drive ( MS Live service)

Yes it will involve a little work with some services.
Basically you move your bookmarks folder to were one of the above listed services sync`s and change your browser to look for its bookmarks there. Presto sync`d book marks.

Sugar sync can be told what folders to sync on a system so no real work other then right click on the bookmarks folder and add to sugar sync.