I've used it several times.
Sometimes it helps resolve a problem, sometimes not...And yes, sometimes it perpetuates a problem...
When I know everything is running extraordinarily well I will sometimes turn it off to clear it out of old restore points that might not have been as "pure" as the current...Then after a day or so, I will turn it back on to create a clean restore point.
Overall, I think it is a good feature and for the most part I will always leave it running...You don't even know its there most of the time.
