I ve been using Zymol waxes on my cars since 2001.
99% of my cars are finished using Vintage wax, the odd, Range Rover, BMW that i sell to my old customers i normally have done with Carbon wax merely as it takes so long to apply the vintage wax by hand to a BMW estate for example.
My detailers are g tech approved so i can offer the facility.
I have tried G tech on some cars, my opinion is
the tech, will last longer and protect the car for longer ,
BUT
the finish is very varnishey, theres not as much depth to the shine as there is with Zymol. g tech have had to modify some of the serums as i found , which they denied for 12 months, which is the main reason i haven't gone down that route, in areas where the atmosphere of has a high salt content, they suffered from water marks that wouldn't go away, as i'm less than half a mile from the sea, i found i had 2 cars tech'd and a fortnight later the water marks wouldn't go away, so the cars were redone and the marks came back again. and then were zymoled.
the water beading properties come from the EXO liquid which is applied last which I'm told should last for about 9 months.
the company to deal with i find are slightly hard sell in their approach, when i tried to buy some they launch into upselling you can charge customers so much, its all about upselling and profit, whereas i'm more i'm looking to buy the product to make my cars look better than everyone elses, they denied all knowledge of the water marks till 18 months later when they sent some samples to my guys and admitted the salt area problem, never mind the £500 id wasted having 2 cars redetailed
so in a nutshell
the finish on with Zymol is deeper, but is harder to maintain as it is a wax and will wash off over time,
the Gtech will last longer, is more expensive, but very varnishy/ wet look and gives a false sort of gloss
Plus is a professional only type of application and some of the prices they try and charge are quite ridiculous
as an alternative to GTech, i have tried some sealants from Maxprotect in kings langley, north west london, small company, a detailer who also sells the product, very helpful and friendly co, who i think details all of JZM's cars
http://max-protect.co.uk
I ve tried it on a midnight Blue 997 and it lasted really well and the shine was deeper and less false than the Gtech,
Plus as the owner is a detailer who also sells the product, he's easier to speak to