Just bought a pair of Rudy Project Rydon glasses. I have tried almost every color out there and came up with the following conclusions:
1) For IPSC/IDPA, to me, there is nothing better than the photochromic clear lenses. These are the lenses that adjust to sunlight. When wearing them all dy, you dont even notice them change (which is great). IPSC targets are cardboard color and the backdrop is usually sand or dirt. Clear is the way to go.
2) For skeet/trap, I always liked the yellow. Seems to me to bring out the orange targets well. I may actually go with the clear for this type of shooting also.