I've gone for the Sigma ring flash. So far I'm impressed with it, although it's still early days. The reported flat image is easily dealt with, the gun has two tubes, which you can vary the intensity, even switching one of them off if you like. This provides good modelling, and removes the flat effect. They're very versatile, with many shooting modes, you can be completely lazy if you like and shoot on auto, (whatever that is!
) But it's also easy to use in manual mode, with plenty of power adjustment.
It'll come into main use with me once the insect season gets fully into gear!