It can’t just be me.
But what I require most from any UI on a multi mode light is consistency. I want to know what it is going to do when I turn it on. Rather than play a gamble on which mode I’ll get.
Sadly, it seems that even after a decade or two of multimode torches, something as simple as this is overlooked by so many manufacturers. :o
I’ve been stung a couple of times.
JetBeam Jet II Pro. An otherwise awesome light in build, size & performance. Let down by a truly dreadful UI. 
The Manker U11 was another great disappointment and utter waste of money, sitting on the shelf being unused due to another appalling UI.
Even some lights I’ve modded and built suffer poor UI’s. I was once a fan of the Qlite driver (as sold by Hank at Int’l Outdoor). Because back in the day it had high output (3amps) in a 17mm driver with constant current and the ability to completely hide the blinky modes.
But the Qlite has “memory”, so when you have it configured for say 4 outputs. It is a complete gamble what you’ll get when you turn it on. It could be 0.5 lumens or a 1000 lumens. You never really will know.
So sadly I’ve largely stopped using these lights. I could replace the drivers. But it is quite an expense to go through all of them, which also makes you think should you replace the LEDs too. And after you’ve done this, you are often at the price point of getting a new Convoy light anyway.
Recently I’d been looking at buying a really cool mini side switch 16340 light. Something tiny and interesting that just makes you think “wow” when you see it. Eventually narrowed it down to a Klarus and On the Road M34. The Klarus I can’t find available to ship to the UK and the M4 turns out to have an unfit UI.
Obviously UI’s are the only buying factor. Tint is also vastly important, plus performance and other design characteristics such as not turning on in your pocket. But a poor UI means I’ll just end up being annoyed with it and not using it. It isn’t something I can work around or forgive in a light. So it becomes wasted money, effort and expectations.
On a larger light (what I’d call coat pocket or bigger lights, sort of C8 sized and up). I have less objections with the UI. Lights such as these are typically going to be used outdoors in larger areas, where the majority of the time you’ll probably want a higher output rather than a lower one. So it doesn’t matter too much if it is bright when you turn it on. Although having predictability and consistence is still a pretty basic want.
But for anything pocket EDC sized, such as a p60 or smaller it really must have the ability to be turned on with 100% certainty in which mode it’ll be. And that certainty needs to be to allow you to turn it on in a low mode. Because indoors, close up and often in total darkness if you awake during the night. You want to have a low output as the first thing you are greeted with. Being blasted with 500-1500 lumens is not a reality you want!
Anyone else feel this way about UI’s and have such bitter disappointment that so many otherwise interesting lights fall so far short of being fit for purpose.
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