There are good reasons why roundabouts are successful in some places, but less so in others.
They work where vehicles are well and randomly dispersed, even if traffic volume is comparatively high. They definitely should not be used when any feeder road has nearby traffic lights.
Stoplights bunch up vehicles, which subsequently arrive all at once, defeating the continuous movement desired by the roundabout.
Many U.K. roundabouts have been overwhelmed by specific feeder volumes so that they have been equipped with traffic lights themselves.
Most intersections without roundabouts also do not have stop signs, but instead are signed Give Way.
Drivers are conditioned to look and blend without stopping. We in North America have been habituated to stop and perhaps do a few chores while waiting to proceed.
David A Kelly,