It has a bad rep, but if you're used to British mini roundabouts, driving on it is a non-event. The regularity actually means it's simpler than other, smaller, but more arbitrary aggregations of mini-roundabouts.
If it's so good why aren't there more of them? Not like England has any shortage of N-way (where N >4) intersections they could be used at.
The wikipedia page says "the roundabout provides a better throughput of traffic than other designs and has an excellent safety record, since traffic moves too slowly to do serious damage in the event of a collision" which to me sounds a lot like someone trying to spin failure to play up the silver lining.
Experimentation with junction design has been a good thing in the UK. Many of the designs are, however, attempts to do as well as possible in the space, because a better design would require compulsorily purchasing some people's houses or gardens. So, although there are not lots of magic roundabouts, there are lots of agglomerations of mini-roundabouts with slightly different topology , many of which are more annoying (but fit in the space, and keep traffic flowing).
However, it does seem likely that this is kept mainly because of its fame. I seem to recall that there was a proposal to replace it which was shouted down.