I had it installed right after I took delivery. It's not cheap. I did the leading edge of the hood, the headlights and upper fenders, rocker panels and lower doors, the leading edges of the ATS flares, and the door edges. I think the total came to , uh, a lot! A co-worker had it on her SL500 and loved it. When I traded in my 98 Quad-cab I was amazed at how many rock chips I had on all the areas that are now Stonegard protected. It's not perfect and does not shine like well waxed paint, and it does wear, but that's the idea. It wears so the paint doesn't have to. You could renew it periodically or take it off after a few years and have a brand new paint job.
Hard for me to says if it's worth if or not yet, but after two years at least I'm not crying over a zillion rock marks.
I had mine installed by AutoTrim in Tukwila WA. You can get what ever you want covered. You could do the entire hood if you desired. Usually they target the damage prone areas first cuz it ain't cheap to have installed.
Seems to me I recall seeing kits offered on line, but I have tried DIY window tint film but I could never get the professional looking job so I didn't think I'd be any happier with the Stonegard.