If you back up Amazing Charts online without the Imported Items, you don't backup Imported Items anywhere. So make sure you back these up separately.
When you backup Imported Items using Amazing Backup, you overwrite the old folder.
I'm sure others backup the Imported Items separately, so I expect some responses to your question. I just backup AC completely (including Imported Items) to a local hard drive, and then copy that file to another drive to bring home daily.
Restoring from the AC online backup could take some time, from what I have read in these posts. I can restore from my local backups in a half hour and get back to work.
