Safari bookmarks won't sync reliably
I have one Mac, one iPhone, and one iPad. iCloud as fine for months, but about a month ago it completely stopped working.
Reading List would still sync, but bookmarks no longer would.
I tried disabling and re-enabling iCloud Safari sync on all three devices. This made syncing work again... for about 12 hours. Now it's broken once again on the iPad. Changes still sync from Mac to iPhone... for the moment.
(And there were ugly side effects of disabling-reenabling: the order of my bookmarks changed so I can no longer see the important ones first, and I lost about a week's worth of Reading List material. Bookmark order can be restored from backup, and I know how to do that via Export/Import, but the Reading List stuff is just gone. So I can't make a habit of backing up, toggling iCloud, and restoring.)
What can I do to make bookmark syncing reliable?
(I'm running a fully up-to-date Lion and iOS 6.)