For years typical LEDs were under 5000 mcd. In the last two years or so, 10-20k mcd standard LEDs became widely available. Very recently, very high power LEDs became available and they can far surpass that level. It appears that the flashlight is using the standard low power 15k mcd LEDs. So as a very crude estimate, imagine the typical LED and make it 3-5 times brighter. Now place 128 of them together. You'll end up with ~500 times as bright as the LEDs you've seen for years. Thus, that flashlight should be bright enough for most needs.
But as others above have mentioned, there is a lie somewhere on the page. 128 of those LEDs will drain those batteries in a couple hours at full brightness. The only way to make it last that long is to turn the brightness way down.
I don't know if they are lying about the battery life or lying about the brightness.