We took a drive through the midwest this summer. Richfield MN has circles in the city, but they are miniscule and everybody has to slow way down to get around. It's not a horrible deal if they are used instead of bumps to slow cars, but it snarls traffic during the rush.
It was in western MN, heading toward SD, that I found the real puzzle. Driving down a 2 lane highway, we came to a traffic circle that required the semi-trailers to slow to about 15 mph in order to be sure they could get through without running their wheels up over one curb or the other. This was on a sunny summer day. I'd be interested to see how well that works in the ice and snow of winter.
When a traffic circle works for smooth flow, it has to be big enough to not give carnival ride type G forces when you go around it at traffic speeds. The traffic circle near me has a median of about 100x200 feet. You can go around this at 35 mph without a worry, and that was maybe the general traffic speed when the road was built.
But the tiny traffic circles I saw in MN have nothing to do with smooth flow of traffic, and should have no place on heavily traveled roads.
I hope Kansas did it better.
Obviously they are not the solution to every situation. It is equally silly to say they are NEVER the best solution.