European and EM Dividend Tax Optimisation

I was looking at the (cool) tax optimisation article and for those of us who do hold ETFs with (western) European stocks what is the best domicile? Most of them are based in Luxembourg. Is this in fact the best option for Swiss residents? Of course, it may be dependant on where the underlying stocks are based but if we assume most are in Germany, France, UK maybe Italy?

What about EMs with the assumption of majority of holdings in China, India and Brazil?