Frontal Stone Guard

Anyone got any thoughts on the most efficient frontal stone chip guard.
Some use a perspex or metal guard mounted on the front bumper. I have no experience of this but wonder how much of the front it actually protects.
Some use an apron pulled up over the bonnet. Seems like a good idea but radicly alters the apperence.
A Line Haul truck i drive has some sort of clear film stuck on to the front that seems to work with out detracting from the appearence. Its four years old and has not discoloured. Anyone got any experience of this. My new paintwork is already getting thrashed.

i used ventureshield clear film on the front of my golf...fantastic stuff. pre cut kit and spent 3/4 day putting it on, bit tricky
but not too difficult.
not sure how you would go if you can't get pre cut.