I have plasti-dipped every bit of chrome and emblems on my Ram and they have held up great.. Did the grill several months ago and drive about 140km of hwy driving a day and the only touch up I ever have had to do was where the grill meets the bug guard. Bumpers have also held up excellend but there is a few spots I want to touch up which were caused by me not being to careful with my taping from the chrome to the plastic.. And I also ran out of plasti-dipp as soon as the back bumper was done so couldn't do touch ups and haven't had time to restock.
Seriously contemplating doing my whole truck for a complete murdered out look.
BTW.. Grill has also survived me taking the truck mudding and offroading.