Zaino is technically a polish only, not a wax...
The advantages:
No matter what wax you use, it will dull in the sun in a matter of days/weeks. Zaino doesn't dull...
The disadvantage:
Some people on Corvette Forums had posted that it doesn't quite protect like a real wax. I.E. Bird shit left on for more than a day could easily acid etch the paint where as with a wax, it'd take much longer...
If you want the utmost in shine... Zaino...
Protection... I'm not saying Zaino is bad, but wax protects better...
If you want was, the longest lasting I've found is the Mcguiars Gold Class...
Keep in mind, the shiny part of wax is usually the silicones in it, not the carnuba(which is actually quite dull). Once the silicone burns off, you get dulling because all that is left is the carnuba.