To the original question...
The Fenix' are great lights, and everyone should own at least one of them.
As to deciding which you want, it's really quite simple.
First, decide which battery you want to use. CR123 lights are shorter than their AA counterparts, but you can go anywhere in the world at any time of day and you will be able to find AA's. Not so with CR123's, so you would have to plan a little better.
Second, decide if you're willing to carry a slightly longer light for the extra brightness and runtime, or if you want decent light but in a very small package.
I love my L2D which I bought specifically because it uses AA batteries, and it's exactly as long as a Maglite AA flashlight but thinner so, for me, it's easy to slip into a pocket and go anywhere.
But most of the 2 cell Fenix lights can be converted to 1 cell by getting the extra, shorter barrel so you have an option.
I'm thinking of getting a P3D "just because", but this L2D does everything I want so I probably won't. I really like my small light to be based on AA batteries from the "survival" aspect.
As far as brightness, and to offer a comparison, my L2D's two highest settings are 107 lumens and 180 lumens (it's a Q5). Yes, it's easy to see the difference between the two settings, but I find that the 107 setting is more than I want or need 70% of the time. For another 10% of the time it's used, I'll use the 180 setting, but for the other 20% of the time, I use the lower settings because in some situations, anything more is just too bright.
I don't join in on all this nitpicky talk about color and if a particular LED makes things look "flat" (?.. I don't get that) because if I want to see something well at night, all I need is a bunch of light.
While I can see how some might like a particular light tint, to me, that's just a preference for what someone thinks is "pretty" rather than for what effectively lights up the night.
God help some of you people if you ever need to use infrared at night.
These comments are worth exactly 2 lumens, so use them or abuse them with that in mind.