Thanks for that article pointing at SF6. Also new to me, makes sense.
As usual in this problem of filling the world with energy, though, it is difficult to deal with the scales involved (a factor of 23000, lifetime of 1000 years, orders of magnitude of uncertainty on leaks). Calculating with very large numbers is difficult, operating with the differences between two very large numbers more even so.
So, it looks really scary, but...
"Each turbine would normally have contained around 5kg of SF6, which, if it leaked into the atmosphere, would add the equivalent of around 117 tonnes of carbon dioxide. This is roughly the same as the annual emissions from 25 cars."
If that journo did not mess up that info (usually happens), we are talking of a full leak from a monster turbine being the warming equivalent of the lifetime emission of about 2 ICE cars, because that same turbine would not keep leaking all its contents each year. Tough trade-off!
Yet, as all changes, this will come with its own new problems. This one is "easy" to regulate away, one painful government at a time.
By the way, really fascinating stuff, this SF6!
https://www.youtube.com/watch?v=U4ixGhtBPp0 
Edit: And as an illustraton of how both sides tend to exxagerate and mould reality in this big debate:
The 23000 factor was arrived to considering the greenhouse potential of the substance over a period of 100 years. Which is an interesting choice for a substance expected to stay in the atmosphere for ten times as long.
Rivals, not enemies.
