XavierMace, you are right, there are a lot of things that make a light better than just brightness.
Beam dissolution - UTG beam stays more concentrated compared to the Surefire M961XM07 weapon light
Beam intensity - From the focal point of the bulb, the UTG has a greater intensity than the Surefire M961XM07 weapon light
Beam concentration - At longer ranges, the UTG light illuminates a more concentrated area
Battery life - The UTG light being an LED bulb sucks less battery power than the Surefire M961XM07 weapon light
Warranty - Surefire has replaced my light when I broke on when it was hit with Sim-unition at Camp Pendleton
Water resistance - Surefire has a tighter seal around the battery compartment and bulb
Accessories - both the UTG and Surefire M961XM07 weapon light can use standard filters and accessories available via Surefire.
I am sure there are more things I can come up with, but over all, the UTG for the price and performance cannot be beat.