I'm not in the law enforcement biz, but I am a flashlight nut, so here are a few personal comments:

My experience with Fenix lights (AA versions) has been mixed. They are VERY bright and very efficient in battery usage. But out of the four I own, one suffered substantial problems. It didn't fail entirely (high mode still works) but it lost low mode and nobody can give me an answer as to why. That has punctured my confidence. I still use them, but I make a point of having a backup light.

In contrast, the five Streamlight LED lights I have are heavy, old tech, bombproof, and utterly reliable. They inspire absolute confidence for me; I have yet to find a reason to doubt their reliability. (I have a wholesale source and need to try out the C4s, which are likely select versions of Cree or Phillips LEDs.)

Anyway, FWIW, If my bacon was on the line I'd carry a Streamlight.