I use the E&C roundabout every day - I find it absolutely fine - i get into a good position, maintain it, signal clearly, and bobs your uncle. I also use the A23 Streatham to Kennington every day - have seen loads of accidents (cyclists, motorbikes) here. Mostly collisions with vehicles pulling out from side streets. Maybe because it is a nice flat stretch of road, when the bus lanes are clear, is easy to build up speed, so vehicles pulling out misjudge the time they have?
On a sweeter note, how fab is it that they are FINALLY resurfacing Borough High Street??! HAve been waiting a looooong time for that!