A few nights ago I finally pulled the trigger and bought myself a ZL H51w after reading many threads and posts by Davidt1. Now I wait for a few weeks until it finally comes in. This said, I have a small collection of lights, and have found that if the H51w specs prove correct, then I think that it would prove to be the best all around light that I have ever owned.
Here is a break down that I have come up with in comparison to the lights I already own.
L2 = 0.18 lm = just below the lowest low of NC D11.2
L1 = 2.2 lm = low of Preon Revo S2
M2 = 7 lm = low of NC EZ AA R5 / just less than E01
M1 = 26 lm = E05
H2 = 86 lm = High of Preon Revo S2
H1 = 172 lm = High of EZAA R5, just above high of D11.2
Here is pretty much my collection, all wrapped up in one neat flashlight package. I hope that the light is as good as many of you have said.