It's good to do the built-in backup, but that gets you only so far. For one thing, you still need to remember to backup whatever is on your SD cards, as the built-in obviously doesn't back up those up. (In fact, that's where it puts the back-up.)

But the built-in back up still makes you go through repository hassles if you restore, and I found it quite problematic. (This is especially true if you installed anything in Red Pill Mode, or if a repository is down.)

The only way I know of to do a comprehensive backup requires first setting up your Tablet to dual-boot from a cloned OS. Then you can do a "real" backup of the MMC, which will have your apps and OS and everything. See my signature, start with Post #2.