Although I have half a bottle of Collinite 845 left, curiosity and an AAP sale prompted me to give this stuff a try.
845 is renown for its durability, and I've found that to be true, especially for a garaged car.
But the allure of an easy-to-use spray wax, and "ceramic" hype made it easy to try something new.
Durability is yet to be determined, but for easy application, the GG wins hands down. Simply spray on, over paint, chrome, plastic, even glass, and wipe off. It doesn't get any easier. No need to worry about white residue on black plastic, crusty accumulation in gaps and crevices, or any similar precautions needed for a traditional wax. No need to dunk the 845 in a warm water bath, or leave it in the sun to de-solidify it.
With the GG, high spots can develop if the panel is too hot and causes it to evaporate too quickly, or if too much product is used, but they can be knocked down with a damp microfiber, but those precautions aren't as severe.
Another respect in which the GG product betters the 845 is in pop. Waxes like Collinite and One Grand Blitz do sacrifice some of that for durability, and after using them for so long, it was evident.
Placebo effect, you say? I don't have a gloss meter for objective measurements, but the results on two cars, one outdoor beater with no prep, and the other with prep work do not deceive, at least subjectively.
For me, those are pluses, so even if it doesn't end up lasting a year (not expected), or even six months, the easy of application make shorter intervals less of a chore, and worth any trade off.