Yes, there are folks with issues. (of course those without them don;t show looking for help).
OK no question 4kb/hr is too slow.
Let's see if there are any clues.
First, are you trying to backup to backups from earlier versions (Lion, Snow Loepard)?
If so sometimes it will just backup the changes, sometimes it wants to take a full lbackup the first time.
These might help in that regard:
But putting that question aside, no matter what it is doing 4kb/hr is too slow so there may be clues in the console log.
Open Console it's in Utilities.
Make sure All Messages at the top of the sidebar is selected.
(If the sidebar doesn't show, select Show Log List which is in the upper right.)
search for messages with 'backupd' in them.
It would be particularly interesting to see the messages that occur when a backup was starting, as well as point when it is "progressing" - slowly for sure!, and other other "strange" looking message related to the backup.
Post them here - not a screen shot - paste them.