So my favorite brand is PIAA's, just out of the brands I have tried and have experience with. The huge benefit from using yellows is you still get GREAT vision, better then your stock headlamps by a lot, but you do not get flashed from oncoming drivers. Also way better in fog and snowout conditions. You can turn off your headlights and drive just as well with just yellow PIAA fogs, so long as the CHP don't getcha. The peripheral vision with PIAA"S is just fkin sick, blew me away when I turned them on for the first time. IMO they should be mandatory, so beneficial to have a high quality fog lamp. But with the high quality fogs, you get in the grey area for offending oncoming traffic with clear. You may not care, but blinding oncoming traffic is not a good idea. With most fogs not really an issue, but the higher quality ones it can be.
Yellow is the way to go.