Tim, that's a good question, I'm wondering the same thing. My A arms were poorly chrome plated about 8 years ago and now the chrome is pitting and coming off.
Nickel plating looks nice (not too flash) but I'm wondering if it has good longevity in the presence of normal road grime and salt, etc. Anodizing could look nice too - there's a gold anodizing that is pretty toned down but, again, have no idea about relative durability.
I imagine that the quality of the prep job, and the skill of the plating shop can make a big difference in the durability.
Sorry to not be more helpful!