Mike:
We have been required to wear reflective vests (I guess what you call jerkins) on a lot of construction sites for some time. That is along with the other PPE like hard hats, safety glasses, footwear, as required. Now keep in mind we are the inspectors. It is Twp. policy, and required on most sites.
Personally, I like the reflective vest, especially when I have inspections at night, or dusk/dawn, and roadside jobs.
I also personally have a few 'hi-vis' shirts.
