I bought a host of Zaino goods many years ago, long before I became a member here. Wanted to see what all the claims were all about. And yes, a couple of bottles of Z2 were in the order.
It wasn't a bad product per se, and like some have said and wondered, was it actually Duragloss #111, which might possibly be the exact same product, but much less expensive. Using both, I'd say they sure are similar in many aspects.
About the only quibble to note about Z2, I thought at times it was a difficult product to remove. Sometimes it didn't seem to dry right, even with the accelerator, it seemed quite "weather dependent", even in New Mexico's dry desert climate.
As for a comparison to Wolfgang's Deep Gloss Paint Sealant, I myself would choose this hands down versus Z2 any day. WGDGPS 3.0 is about the easiest wipe on wipe off Sealant I have ever used bar none, and the look it delivers is superb.
Only one other Sealant I liked quite a bit years ago, and used quite a bit of it, was Meguairs #20 Professional Polymer Sealant.
Of course, one should use what they like.