At the risk of getting into a lies, damned lies and statistics argument, I'd like to comment on some issues here. I was involved in the investigation of the Swains Reef accident and there were many issues not just one...and it had nothing to do with single vs twin. There are issues about flying over water at night and there are issues about management practices. I also looked into accident rates and in Australia over a 10 to 15 year period, a piston engine helicopter was roughly twice as likely to prang a single turbine which was more than twice as likely to prang as a twin. But when I looked more deeply at the individual accidents, very few had anything to do with the powerplant! It seems a better measure was how expensive the machines were! Simple stats ignore the role of the machines (mustering vs HEMS vs tour) and ignore the level of supervision and training.
There is, I believe, a very big issue about night ops in Australia and there is and will be a lively debate about the use of Night Vision Devices and things like Night VFR. My own personal belief is that if you can't fly with reference to a valid visual horizon, you are effectively flying IFR. We should bring in NVDs as soon as practicable provided the equipment, training and currency issues are addressed. The HAA is doing some good work here.
Just my two pennies worth.