Orange props are definitely the easiest for me to see.
Indoors: I find white easier to see than black.
Outdoors: white is slightly easier to see than black for me (even with clouds as a background), but not by much.
I ended up with this prop color scheme (to evenly use up all the black and white props that I have):
Originally Posted by Balr14
I use one black, one white and two orange blades.
My front props sometimes get bent from crashes (I then do some unbending with heat).