I am afraid that for some reason my M4 came with a MN61 in the light, and a spare MN61 module, so, alas, I have no MN60 to test. I fear this is a case of 'I would, if I could; but I can't, so I won't'. It does seem rather odd that SureFire would give me two of the high power bulbs, doesn't it. My guess is that a M4 w/MN60 = UltraStinger, at less than half the price. I did just trot out onto the porch, and tried the UltraStinger against my M3 w/MN10, and found them to be almost identical, with very,very similar amount of St. Pauls being lit up. Therefore, a M3/UltraStinger is probably a better comparison. I must qualify my tests by restating that my UltraStinger is only a week and a half old, and the owners manual does say that it will take several battery cycles for the battery to be functioning at full efficiency, so the thing may get slightly more powerful over the next months.