We’ve had our circle for +\-1 year. At first it seemed like it was blocking things that it shouldn’t be. Once we figured out how to look at the history of blocked sites and how to add the to approved websites, things worked well since.
Negatives: I noticed a slowdown of performance for all our devices. For work I have to use real estate websites that took forever to load with the circle filtering. Also, if you don’t pay for the extended service, I can just drop off the WiFi and use cell data to go to blocked sites.