Surefire make good lights main drawback for them is there use of cr123 lithum cells.for a short term emergency cr123 is fine, for a longer one i am non to sure. i live in the UK and finding a supply of good quality cr123 cells is difficult at best.

rechargable rcr123's i have to get from china quote capacities are iffy at best 880mah cells normally test out to around 500-550 mah. the cells also become old quickly depending on how they are stored and used. generally requiring replacement after 18-24 months as they can no longer hold there charge. not to mention hazzards like catching fire while charging if using unprotected cells especially. newer chemistry cells remove the fire hazzard but have half the capacity.

for my emergency lights i have gone for AA type with eneloops rechargables and 8 lithium aa cells per light.