Well I've given this a few more goes over the months and I'm still not very happy.
I think anyone using it on a windscreen will be very unhappy with it's performance.
I generally like the performance for big sized rain drops that really clean the screen off, but on a partially dusty screen between washes, with fine misty rain, it's just dire. It's worse than having no sealant on in those cases as the droplets kinda shatter into finer droplets and mist over the screen.
Wipers then just seem to smear unless the glass is really clean.
It's ok for side windows and stuff though, and £10 or so for what must be 10 years worth seems reasonable enough I suppose... but I think something like AG EGP would be just as good for side window glass... and it's cheaper.
Certainly an avoid product imo.
I'm kinda unsure what actual use it has... and what people who like it actually use it for!
So far I've used it on house windows more than my car