I finally gave up on a SWM V10R - down the road.
Why? the high-quality system was operable with one hand, the variable ring worked smoothly, the highest output was available with a "click", but the ring moved too easily and often the setting/output seemed to change by itself. Furthermore, the run-time is nebulous with a fully variable setting. Also, the ocassional high output whenever the light came close to a radio speaker (magnet) was irritating.
Why? When I use my lights, if they are not tail-standing, I very often change the light output. For a variable ring system, that means my fingers are resting on the ring during use. Unfortunately my fingers inadvertently pressure the ring to one side or the other unless the ring movement is more restricted. Even w/in the SWM system, the V60 ring has more damping/viscous movement than the V10. Unfortunately to achieve the highest output with the V60, I have to rotate thru the lowest levels - which gives plenty of warning to whatever I am trying to pick up in the woods. I would strongly prefer that the highest output is available instantly - which the V10 does provide. eh, na ja, the V60 will probably follow the V10 out the door.
IOW, Tail-standing is a high priority - meaning no "tactical" switches (light is not on a weapon). One-handed operation for on/off or switching multiple levels. An option for the highest output first. Multiple clicks on a tail switch or multiple twists w/in a second or two to reach some other output is maybe OK for me, but that system challenges many of the recipients of gifted lights - which results in them rarely using the other levels. Rotating the head to a fixed position for a simple high or low output seems to be ok (EagleTac). Lights with only two levels (LD-15), although a head-twist, also seem to be OK for gifting. Side-clickies from ZL or Fenix seem to be OK. Not quite sure about multiple buttons on the side for on/off and output level - potential of confusing the buttons.
As always, YMMV. However for me, several months of using several copies of the Zebralight UI has been rewarding. One quibble with the ZL system is the light "touch" to the earlier switches - which then requires a lockout twist on the tail-cap when carrying a ZL in a pocket, and thereby slows down an initial use. The SC600 switch pressure has been OK though.
and I am satisfied that my requirement for about an hour or more run-time on _high_ was correct.