It might depend on engine type, but, I've found for the coil version fitted to the 1.2 and 1.4 engines, Eldor is my manufacturer of choice - try to avoid accepting any built in Turkey though as that is where most of the problems with Eldor came from. Bosch is a quality manufacturer, but in my experience not necessarily any good at making these coils. Beru - I've only ever had one Beru coil and it failed after 14 months.
It is all down to how anyone builds these compact high voltage assembles - and seals them against moisture ingress.