I first got the A3 and really liked it a lot.
It was the perfect mini light.
Then I got the A1 to see how much brighter a 3v setup with CR123 would be.
Having both I just got the A2 as well, more to complete the range than anything else.
Its now become my favourite of the lot as a general use torch. The A3 is great for keychain or neck lanyard, but if size in not a factor the AA version is better.
You just know its going to run for twice as long.
Its hard to explain, the A3 is light I USE while the A2 is a light I DEPEND on.
Its hanging on a lanyard next to my bed for power failures and such.
When I go camping I decide on a battery format and take cells and chargers for that size. Last time it was the RCR123/CR123 turn and I took the A1 with as a lanyard light.
When I take AA's then the A2 does this job.
The A3 stays near to home on its light duty role. Must be a distrust/dislike in AAA for anything but occasional carry and utility. Scenarios where I wont use the light for long periods.
Its also got to do with the feel and heft of the torch. The A2 is just right in the hand. I love it.
Once you notice the PWM flicker on the A3 you just know its there. From then on its not the same.
The A2 does not visibly suffer from this.