I have tried Meguiars, Turtlewax, AutoGlym, P21S but my favourite has to be A1 Speed Wax Plus 3 from OK Wack Chemie. Nanotech or such like

No staining to plastic, no streaking, quick to apply, no smears, deep lustre and can last for several months, not that I wait that long. And best of all its about 8 quid for a half litre bottle.

Got best carwax award from Auto Express and AutoBild.