This.
The beam shapes are going to be different for a reflector and a lens. The internal reflecting lens will give you a pencil shaped beam. This can be very useful in specific situations, especially when you only need a dim light but you want it to shine far or show a clear beam.
Another...
In my work it is really useful to have a light with PWM. I can easily show off where there is water leaking, or I can highlight something with a fan or a motor spinning. The strobe effect is useful just to get the customer's attention.
I'm looking for good AA or AAA lights, only.
The only...
Sometimes I want to show off for my friends how bright my new little flashlight is, but most of the time I'm just frantically trying to get past the boost mode and back to dim so I don't blind anybody.