I've done my blue Raptor about the same as OP has: bumpers, skid plate, flares, reflectors, wheels, wheel wells, and rear Ford emblem. So far everything has held up pretty well. Rock chips aren't an issue. It works pretty well as protection against rocks. Rubbing or scraping, especially along an edge will cause it to peel. Touch ups are easy but they are usually pretty easy to see where it was done.
One thing I did learn from doing the rear emblem and the flares was how to properly mask for this stuff. Overspray really isn't that big of an issue since you can just peel or rub it off. It is a little easier to mask though and avoid getting the little flecks of overspray that can be hard to find if you have a darker colored truck. Instead of trying to mask right next to what you're spraying like on the flares and emblem, you should leave a 1 or 2 inch gap around them. The overspray there will be thick enough that you can peel it off in a sheet and it won't disturb the part that you wanted covered. If you do try to mask right next to the emblem or flares, when you pull the masking off it will start to peel off the part you wanted covered.