I have one and I like it. It is not quite as bright as the XLR250 kill light but brighter than the 100 scan light. It does spill some light so I added a halo shield and took care of that. I do not use it as my primary scan/kill light, I prefer a hand held scan light and a gun mounted kill light but I do use it occasionally for scanning and always while walking in/out to a stand. I have found it to be very handy.
Just watch that you don't illuminate yourself, and take the time to make sure that the headlight is properly adjusted on your head so that you can see the animal in your sights and I think you'll be ok with the W13 as a primary light if you're using a shotgun. I recommend a dedicated gun mounted kill light for a rifle.