I must drink the same water as VOS.
While I have UPS on multiple units here, and cannot remember the last time any of them came into use...
That said...UPS provides the insurance of avoiding significant power-related problems. It only takes one time to lose a hard drive or some other hardware to regret not having a UPS.
Well, you Never have the problems that a lot of us have so it would figure that you wouldn't have Rebooting Problems.
That said you won't to do everything possible to keep your DVR and it's hard drive healthy and that is why a UPS helps by giving it clean regulated power and keeping it from having a sudden power shutdown which along with Heat is the hardest thing on a hard drive.
Also, it is very annoying when you are watching something such as a Great Football Game or a Golf Tournament and now you find yourself waiting 10 minutes or longer for the DVR to finish it's Rebooting Process which can be easily avoided by a UPS.
A couple of weeks ago we had a Severe Storm headed for Peachtree City and my lights flickered but my DVRs did Not Reboot. I am a Happy Camper!!!