I have one. Use it every day since i got it about 2 months ago.
I am very happy with this light. Very slim, very lightweight. Output is about 70-80% of that of a Q3 with normal CR123.
Its a little longer than the Q3 but much more slim, so carrying it in a pocket is no problem.
I like the beam of that light very much! Huge decent sidespill, small bright hotspot.
Sidespill is ideal for navigating around in the house, the hotspot is bright enough for illuminating things or persons up to 10 meters i would say.
I never missed the bigger brightness of my Q3 and instead of carrying two lights (Q3 and McKinley) i only carry one at the moment.
Runtime might appear a bit short on Alkaline, but you get much more light for the money compared to running your Q3 on CR123.
Running the KB on NiMh is the cheapest of course...
size comparison:
beam comparison:
KB on the left, Q3 on the right. (Beam colors are not realistic in this picture)