rotary is the version that is sold most of. Hogo mentioned it is ~9 rotaries 1 Clicky ratio....
Long time ago I made a review of the regular Body types of the Rotary (CR123, 18650, 2xAA) in a german forum. Important the measurement is metric!
[bimg width=600]https://i.imgur.com/geV9onc.jpg[/bimg]
[bimg width=600]https://i.imgur.com/fG0f853.jpg[/bimg]
And a size compare with the Surefire Outdoorsman lights (2xAA, 2xCR123, 1xCR123)
[bimg width=600]https://i.imgur.com/rxXImfY.jpg[/bimg]
That is the most difficult question since there are mostly some preferences, like warm color, or a cooler color, ....
A lot people will say NB45, and I agree with them, NB45 is great. But I personally prefer the NB40 a bit more. But that does not mean NB45 is bad!
Only to give you a feeling about the colors here an old picture of a compare of HDS LED options taken in mid 2018:
[bimg width=600]https://i.imgur.com/UUvg6hU.jpg[/bimg]
The Nichia 219C and the currently offered 219B are somehow comparable. The 219B is mostly a bit more rosy due to the fact the white light has more red.
Here is a compare of NB30, NB35, NB40 and NB45 I took in September 2022 on request.
[bimg width=600]https://i.imgur.com/XiU7SlN.jpg[/bimg]
Also in this thread are some smaller light color compares of other members of the current LED options, but for this you must search for it on your own.