Here's another approach you might consider...
Use a large external, USB (or Thunderbolt) drive partitioned into 2 drives (Disk Utility makes this task simple) - 1 partition can be set up as a Time Machine & 1 for SuperDuper clones. The direct connect will enable really fast backups, and with the TM partition always connected (and the drive On), you'll take advantage of the hourly backups like a Time Capsule (when your MBP Retina isn't in Sleep mode) as well as being able to do periodic clones.
For real safety, you might consider using 2 external drives (both partitioned as above) so you can periodically swap the drives for respective backups. So, if one of the external drive fails, you've got a recent backup. I employ this strategy by swapping my 2d drive once a week (minimally); and by doing so, I rest easy about possible drive failure.
