I'm attempting Ecto Cooler through a Vivi Nova mini. So far it's not working very well but I think it's because of poorly manufactured heads. I haven't been able to get a good pull and what I am getting tastes a little cardboardy. The first head I tried burnt out and the other two seem to have the coil wound too closely together. The juice has been in there for about two days and I haven't noticed any clouding or crazing and only minor leaking.
If you have genuine Vivis you shouldn't have any leaking issues .. I have 8 of them and never had even the slightest leaking from any of them.