We used to have a roundabout in the centre of our town but at rush hours the traffic tailed back about half a mile so they replaced it with a traffic lit junction and now it tails back over a mile and you even have to wait in the middle of the night when noone else is on the road! In general I prefer roundabouts at large junctions as long as some idiot doesn't introduce trafic lights on them too. The roundabouts I detest are the silly ones painted on the road at small junctions where it is almost impossible for anything bigger than a mini to turn round and can be lethal on a motor bike (so I'm told). Used correctly a roundabout keeps traffic moving whereas by definition lights stop them.