I am relatively new to modern flashlights but the second thing I have discovered about them, after their addictive performance, is how confusing their UI's can be for me, if I own many of them. Half press, full press, single click, double clicks, twisting the head clockwise and then anti-clockwise, and all this in either fast sequence, or slow; resulting in different levels or modes… I am now carrying the user manuals of some of my flashlights in their holsters (and referring to them after accidentally turning them on at turbo!). Nevertheless, a description like "half-press" or "in less than one second" does not mean exactly the same thing according to different manufacturers so, even the manuals may not be of great help, sometimes.
All this started when I decided to renew my old 6D Maglite with a Fenix TK71. What a difference (in terms of illumination!)… Then, I renewed my old no-name head-lamp with a Surefire Maximus. After getting the taste of having more lumens than I actually needed, a Nitecore TM15 was my next joy (the TM26 was not yet released). Then, I bought an EagleTac G25C2. This was before a Klarus MiX6SS became my pocket EDC. My addiction was building-up but even if my new Nitecore EA4 had similar UI as my TM15, I was still forgetting how to operate so many flashlights, with the exception of the Maximus (thanks to its rotary dial).
After replacing my G25C2 with a Nitecore SRT5, however, I never forget how to operate it. This is no different than the volume knob of an old-school audio device. The logic is either intuitive or already pre-set in my memory. I don't have to memorize, once again, that rotating clockwise increases and rotating counter-clockwise decreases the intensity. This is so straightforward. The same applies to the tail clicky: One click means "on", another click means "off". That is it and that is all. I am now replacing my MiX6SS with a Niteye 10TIC and I regret that I didn't get something like the Niteye 30 instead of the TM15 for the sake of its rotary adjustment. I hope the next Tiny Monster comes with a rotary dial. Or, shall I hope the opposite so that I can resist my urge to buy another hyper-lumen flashlight, simply because I will not forget how to operate it?...
I may be too old (I am 58) for so many flashlights with different UI's. No other flashlight for me, from now on, unless it has a rotary dial (and zillion lumens and/or candela, of course). For me, what matters is that the dial is rotary but not necessarily that it is a magnetic ring or that it is infinitely adjustable. I can do with detents for well-spaced levels. When the size of the flashlight does not matter as much, an additional clicky ON/OFF switch could be handy, though. Just my 2 cents.