I used Zymol for 15 years on many new cars and switched to Zaino last year. I have to say the Zaino protects longer based on the water beading on the car.
The shine is also very good although I think the Zymol makes the metallic pop a bit more when first applied.
Current Ride - 2011 328i Convertible - AT, Nav w/Sirius, JB/Cream Beige
Past - 2008 BMW 335xi Coupe (ED), 2003 BMW 530i, 1999 BMW 528i