I had it on my new car in March as I live in the sticks and was aware of just how much salt was on the roads still from the winter etc. My dealer is quite a way away from me which would mean the car would collect quite a bit of muck getting it home. I also couldn't guarantee the conditions (weather wise) that we would get, allowing me to wax it etc close to when I picked it up. At the dealer, the Lifeshine is applied in a heated room. I wanted protection before I left the Audi garage.
I am glad I got it. I have washed it 3 times and the dirt comes off really easy, including the yellow stains that previous threads have mentioned showing on white (although there were only a few on one occassion to be honest).
The car cleaning kit you get with it is great too and it all works really well.
Yes, it is very overly expensive unless you are lucky enough to have it thrown in etc, but for me, who intends to keep the car for 4 or 5 years, then the guarantee is worth something too to me.
However, I have bought some wax and will be giving the car a coat soon, now we have the weather to do it.