I was looking for suggestions for a good survival flashlight.

I think some clarification would help. "Survival" could mean so many different things to people. Intended use? Size? Cost? Preferred battery type? How much light do you need? Are you OK with a headlamp?

Yes, intended use is important. Escaping a dark building? Signaling? Searching for others that may be lost? Reading or doing other close at hand work?

You may not need a light at all for a real survival situation, but a powerful light may save your life. Most camping and living in the woods only requires a relatively low power light just to see what you are doing.

Signaling needs more power to reach potential rescuers.

Searching for others does require more power.

I EDC a Block Light that attaches to a 9 volt battery. It is good enough for most uses. I also have an 1100 lumen Streamlight as I am generally responsible for the safety of others, and it makes it easier to find them.

I also have a good headlamp (I have several brands and models around) as I find them useful when I need my hands for other tasks.

So many variable to consider.