I should chime in here as I've been using NXT 2.0 regularly on a particular race car that I prep before each event (Integra). Note that I have zero experience with Zaino though.
The first detail was a wash (OCW), clay, AIO (poli-seal) and topped with NXT 2.0. This detail was performed on May 23rd, 2008. After I was finished that day, I detailed the other race car, then went back to the Integra and sprayed water on it to get an idea of the beading. (I was anxious to use NXT 2.0 as the hype was built up and I had obtained a bottle from the Megs kit). Unfortunately I don't have pictures anymore as someone lost my camera which had all of the pictures on it
On June 13th (21 days later) I showed up to perform a maintenance detail (wash (OCW), reseal with NXT 2.0). While doing the wash, the water was beading like crazy...honestly as though it had JUST been waxed. I noticed a very small decrease in the way the water was reacting on the paint.
The 3rd maintenance detail was performed this past Wednesday, August 27th (75 days later).
To my surprise, the paint was still showing signs of the NXT 2.0. The car was extremely dirty, so I washed with CWG @ paint cleanser dilution. I would have to honestly say that it was at about 50-60%. Obviously this is very subjective, so hopefully my work will stand for something in this observation. The water was sheeting off and leaving almost nothing to dry, and the water beads were still fairly tight. It was definitely time for a touch up (to our standards), but I am sure it could have gone on for another few weeks before nothing was left.
As for the car itself, it is a daily driven Black Acura Integra, raced in the Solosprint Series by Stage Four Motorsports. Heavily driven and abused and the paint has still stood up to the beating. After using NXT 2.0 I'm pretty confident in saying that it protects very well and lasts quite a long time.