I found this thread to be interesting. It has BEAMSHOTS from a great variety of triple XM-L lamps, along with a few others for reference like TK 70 and some smaller ones.
It covers the 2 skyrays and the trustfire. The Skyray 3XT6-850 is really strong! But from my reading, it is unreliable? Kinda surprising since its only 2 18650s.