I consider it the ultimate keychain light. I believe it is about the smallest, toughest and probably the brightest. It has the most versatile UI while being simple to use. I prefer the covert version because it has no back-spill. I have a Freedom, an X-light as well as the older Photon II and Photon 3, all in white and some in red. I have been using them for many years. I have also tried the Inovas, Princeton Tech, and some others.
If you are worried about accidental activation, there are several ways to deal with that. It does have auto-shutoff as a hidden feature that can be activated or disabled. It could also be put into signal mode so it won't latch on. Or you can cover the switch with a snap-on accessory that comes with it that is intended as a base for a lanyard.
The variable brightness comes in handy when trying to preserve night vision or avoid distrubing others when they are sleeping. I suppose it would also be useful for military or police if they are trying to remain hidden but need a bit of light. It would also extend runtime considerably. I have never needed any of the flashing modes, but the UI is set up so that they never get in the way.
The X-light is very similar, but slightly larger, less water resistant and with the clear body, has more backspill. Both are bright, have the same UI and make a fine keychain light. I like the rubbery switch on the X-light better and it is even made of glow-in-the-dark material. Overall, I prefer the Freedom slightly.
The battery change is a little fiddly, but most coin cell lights are just as fiddly or worse. I wouldn't want to change batteries in the dark, but otherwise it is manageable. The batteries seem to last a very long time. I use mine daily and many months pass between battery changes.