Both of UK2L and Scorpion is good light. While Scorpion is weather proof (work well in rainy day) but not water proof like 2L. Scorpion has tailcap switch which is helpful for many people. Due to its tailcap switch, you will tend to keep the light on for shorter time than one with twisted switch, thus waste less battery. Due to the same reason, the bulb last shorter life than 2L because of more frequent on/off burst. The twisted switch of 2L will not accidentally turn on in a messy pack. For Scorpion, you need a good holster to keep its tailswitch from turning on in a pack.
2L is lighter than Scorpion and I believe 2L would survive better on drop test. Scorpion is much brighter and whiter than 2L.
Alan