To answer your original question, I have used both Meguiars products and would give the nod to the NXT. VERY easy to use, VERY nice shine and reportedly very long lasting (I only tried it for the first time a couple days ago). It is also relatively inexpensive and doesn't require and twelve step process and the better part of a weekend to use.
I have not used the Zaino products, but those that do swear by them. I have used some pretty high end multi-step Zymol products and I find the NXT gives very nearly the same results at a fraction of the price and effort. If you have both time and money in abundance, the Zymol stuff is quite excellent.
Jaeger