I'm not a Zaino user, but I thought ZFX's function was to cause the Zaino sealants to cure faster for layering. Does it add durability to the sealant? My understanding from skimming some of the Polycharger threads is that it makes whatever sealant you add it to much more durable.
Anyway, a lot of the hype surrounding RDF49 and the Polycharger seems to revolve for the most part around durability. Personally, if there were a product out there that you could apply once to your car and it protected it forever I would never buy it. I could make a laundry list of reasons as to why extended durability is meaningless to me, but it all comes down to the fact that I really enjoy washing my car weekly and waxing it monthly. I find it fun & relaxing. Plus, I've yet to find a sealant that from my perspective can match the eye pleasing look of a good carnauba.