I actually performed a Zymol vs. Meguiar's test on my hood - cleaned both halves with Meguiar's Paint Cleaner and put 2 coats each of Meguiar's Cleaner Wax on one half and Zymol on the other.
I washed once a week and used E1 Wet ocassionally. After 30 days, they were virtually the same - non-existent.
On the E1 Wet subject, I prefer it over Meguiar's Detail Spray. Meguiar's seemed to leave streaks and the E1 Wet seems to come off a lot easier.
