The debate about lead free solders seem to be nearly as politically charged as
that about anthropogenic global warming and a casualty seems to be useful data.

I've read plenty of comments to the effect that lead-free is less reliable in
the long term (vibration seems to be a key weakness AIUI - maybe also thermal
cycling) which presumably explains the exemptions for certain categories, yet
I've also seen some studies that claim it can out-perform lead containing
solders.

Is there any real hard and fast information out there that one can rely on ?

Graham