... I have no idea what bin #s or r2, r3 & r5 mean. ...
Bin number is a brightness rating for the LED and each company has their own method. Cree uses a mixture of letter an number. The letter (P,Q,R,S...) tell you generally where the LED is in terms of brightness, with A being the lowest, and the later letters of the alphabet being higher. Then the numbers tell you where in that output (P, Q, R, etc.) that LED falls, with higher numbers being brighter, so a R2 will be a bit dimmer than a R4, but a greater percentage brighter than a Q2. Personally, I don't recall seeing any bins lower than a P2.
But brightness isn't everything. Neutral white and Warm white LEDs have a lower bin rating than cool white LEDs, but provide better color rendering than cool white LEDs. Instead of looking a bit blueish, neutral white LEDs are creamy white, while warm white LEDs are a bit yellow (IMO). So a Q2 bin warm white LED is dimmer than a R4 bin cool white LED, but the Q2 warm white will give you better colors than the cool white LED, at least in my limited experience (I only have one neutral white LED light and no warm white ones, but I have seen plenty of pictures). Usually flashlights using warm or neutral LEDs will tell you in the title, description, or both.
Brightness and color rendering aside, for throw, the size of the emitter is also important. Say you have a foot wide reflector. Assuming the same output, a light source the size of a pin head will project further with that reflector than a light source the size of your palm. This has to do with how much light is emitted per surface area. The light source with more light output per unit area will project than a light source with less light output per unit area with the same reflector.
I won't believe the 300 Lumen claim for the P20A2 R5 (at least not in terms of out the front lumens), but from what I've read, it is a good light.
I think most, if not all of the lights discussed in this thread
have been reviewed here. That site also has lux ratings (Higher lux = more throw). From there, it seems like the P100A2 XP-E edition has the most throw.