A piece of advice from someone who learned the hard way.
make sure you have latest ver of busybox BEFORE making your backups on previous ROMS. If you don't you might get force closes or things not updating.
I went through this on my last update..... kept getting FC on browser after doing titanium backup restore.... so I tried updating busybox and would still get FC. So finally I restored old ROM and went to make another backup.... it was then that I noticed that I had older ver of busybox. So I updated it. Then made backup and then restored to new ROM and did restore.... worked perfectly.
So I thought I would share.