"I use Time Machine to make backups of my user folder and use CarbonCopyCloner to make a bootable backup of my entire MBP's SSD.
Therefore I have the best of both worlds and can troubleshoot via the external Mac OS X clone, if the need arrives."
I would like to second the above posting.
Instead of Time Machine, I suggest that you pick the 2.5" external of your choice, and then use CarbonCopyCloner to create a bootable backup of your "main" drive.
No, CCC does not work "automatically" as does TM (although CCC _can_ be set up to run on a "scheduled basis"). You have to run it yourself. But it will provide you with far better "backup protection" that will TM, especially in the following situations:
- you can't boot from your main drive and need to get running again, as in RIGHT NOW.
- you need a file and can't "get at" your TM backup (seems to be a common problem from the number of postings I see about that type of occurrence in here)
- you want to run maintenance on your main drive and you need to boot from an external source.
CCC even has the option to "leave existing folders alone" during its backups (which means you could keep a folder with your "documents on the go" on your backup drive, and that folder wouldn't be disturbed.
And CCC can even "archive changed files" that would normally be removed during the course of a "cloned backup".
Best of all, it's free.