Glass that does Scratch
If you check the black writing on the bottom of your window and its marked with E1 in a black circle it will scratch easily.
VW Golf is the only car I know of that uses this glass.
Why Tint-a-Car
You'll find that smaller tinting business's will generally have better prices then the larger companies and provide better quality. the tinters at tint a car specialise in tinting many cars per day, rushing their jobs, not getting all of the moisture out from under the film. Thus making them bubble after 1.5 years.
A smaller business just shows a bit more "love" towards the car