Trigger, I'm using two right now. They are very white to almost barely yellow in my eye. Been running these for 4 months or so. The few corals I have seem fine. Coraline algae "may" be off a bit.
Ballast make a big difference in color. Magnetic ballast it looks yellow, Electronic you get a better white crisp look. Either way my SPS growth under the XM 10k's was fantastic. I like the look of the 14 to 15k better but growth seems to be really slow.