It all depends on what you want. Time Machine gives you the option to go back and find files you've deleted by mistake, or that you've edited and want to get an earlier version whereas SuperDuper! is a snapshot of your current system exactly as is.
I use both!
My System drive which contains the OS and applications is backed up by SuperDuper! to a separate drive so if that device fails, I can simply swap them over and carry on working and I have Time Machine running on both the system drive and my home directory so all my data and media is on there.