I've also heard there is a 99 cents "unroot" app that works for any root technique, but I havent tested it. Aside from that, since you're not actually installing a custom rom, it's relatively easy to go into recovery mode and run a "Factory Reset", to restore the phone in case you've messed anything up. I had to do this a few times for mine, but never got myself into any real trouble.
Now it'd be an entirely different story if you were trying to flash a new ROM. I dont think that's safe yet for the Razr. But rooting is pretty streamlined.