"Currently, add-on sync leaves setting synchronization to the individual add-on. If an add-on has support for syncing settings, they will be synced. If not, they won't. For now, if an add-on doesn't preserve settings during Sync, you should contact the add-on's author and request Sync support."
On the other hand Firefox actually lets you move your profile folder from one computer to another without throwing up a panic flag and resetting everything.
https://wiki.mozilla.org/Services/Sync/Addon_Sync