Here is the Ultrafire WF-501B with the Cree drop-in on high vs DiNotte 140L-AA-R on high in side-by-side ceiling beamshots ... The Ultrafire's deep reflector gives a fairly narrow very bright beam with nice spill outside the central beam. The DiNotte is the opposite; it has a very shallow reflector and stepped-type lens resulting in a relatively broad even beam than is not as bright in the center. In flashlight terminology, the Ultrafire is a "thrower" while the DiNotte is "floody".

Which is better? It depends. If you want to be seen from a greater distance in back of your bicycle, for example riding at night on a relatively straight, high speed road with few intersections, I think the Ultrafire is a bit better (with the flashing/strobe Cree drop-in). On the other hand, if you are in lower speed limit residential streets with lots of intersections, the DiNotte may be better because of its wider beam. On a dollar basis, once you have invested in the 18650 batteries and a good charger, you could buy several Ultrafires and get about as wide and bright a beam as you want versus a DiNotte or two. (p.s. and have better control over where the beams go; you could have a horizontal distribution of beams that would minimize glare).

My impression is the total lumens of the two lights are roughly equal but you would need an integrating sphere to sum up all the light from all the angles to really tell.

I provide two exposures because one picture from any camera is incapable of recording the wide range of light intensity that your eyes can perceive. Even these two, one with a fourth the exposue of the other, do not represent what they look like; both beams are entirely red but the central beam is so bright that the camera sensors are saturated and record it as "white". Our eyes are capable of perceiving about 12 stops or 2^12 in a scene while a camera records about 5 to 6 stops or only 2^5 or 6. A better technique is to do high dynamic range photography ...