We covered the larger sibling to this light, the TMT (Tactical Mission Torch) L3, last week, and many of the features are the same between the two. Both incorporate the unique shut-off lever on the tailcap, both have a "high" and "low" setting and both come with a pocket clip permanently attached to the flashlight.
The 5.11 Tactical TMT L2 is smaller and uses one less CR123 battery (although the two it requires are included, like the 3 for the L3). It puts out 638 lumens on the high setting and 52 lumens on low, and lasts 3 hours and 24 hours, respectively. Range is also slightly less, with 178 meters for the high setting compared to 205 meters for the L3. The low setting, of course, is very similar between the two lights. The L2 is a smaller size for everyday carry, though, and fits in a pocket better than the L3.
One thing noticed about both lights is that the lockout switch can be used to activate the light nearly silently. If the power switch is locked out, and the tailcap button depressed, the light will not come on; once the lockout is removed, however, the light is activated without further pressing the tailcap. This is of interest for quiet activation, in that the lockout ring is much quieter than the tailcap switch.