"Plastic look"
The "Plastic Look" that people describe is due to poor prep work prior to Zaino. Most is left over oils/silicone and other is not using a really good fine polish to obtain the mirror shine you need prior to a sealant like Zaino.
Zaino "amplifies" whatever was left on the finish. If it's not fully polished or oils and or silicone is left, it can lead to a haze under it giving a false look or "plastic" effect. The oils/silicone interact with Zaino as it tries to bond. That's why it looks so "funky".
With the Lexus SC430, I used 3M PIII-MG with a polish pad. Following that, I used Glue-Zerna oh, sorry, Menzerna-FP with just a finish grey/black pad as I wanted the polish alone to burnish the finish to a high gloss. Once all polishing was done, I washed the finish with Dawn, followed by Z7 to remove any Dawn film. Then, a spray of distilled water/alcohol mix was used to further the finish by final removal of all oils left b y polishes. Wiped, then applied Z6 prior to a mix of ZFX/Z5 (even though polished, I felt it builds the level) up to 3 coats. Following that, 3 coats of ZFX/Z2. Z6 was used between each and every application.
As you can see from the pic, it was very glossy. Here is another:
All that's needed, no matter if it's Zaino or other sealants is a full polish/prep. If one does not have time for all this work, then stay with carnuba, as the oils/silicone act well with wax when it's applied. It helps the wax "float" and help it migrate to the finish. Good results can be had with S100, Souveran, or other waxes.
Sealants are a bit more labor intensive if you want it done right. Skip the details, and you get that "funky, plastic" look.
Regards,
Deanski