UIs are not only for software. A good user interface just the right amount and type of displays, knobs and switches, and it behaves just so that you need minimum effort to operate and to reach maximum satisfaction. When it comes to alarm clocks, one in particular wins the race, hands down.
I bought my first Casio DQ-852 around 1998. I had to leave it behind for someone else but I was already hooked so I bought one more around 2000. It is so elegant in its design that I've been using it ever since. Unfortunately it is not in production any more, so I'm not looking forward to the time it breaks (which it will, eventually).
This model get virtually everything right. What makes it so good? In a nutshell:
First, the display: a simple LCD. It has large numbers for the current time. More importantly, it always shows the alarm time as well - and of course whether your alarm is currently on or not, and if it's using snooze. You really need this, and only this, from an alarm clock. Current date or day-of-week and room temperatures could be extra, but hardly that important during the night.
The backlight is usually off. And that's how it should be, as you shouldn't blast your eyes during the night with bright lights. If you press the light button, it comes on in a somewhat brighter mode, for three seconds, then goes back to whatever it was before. Three seconds is really all you need if you want to check the current time half-asleep. Perfect. Besides this, the backlight automatically comes on in a very gentle, really dim mode, precisely 8 hours before the alarm is scheduled to go off. The fact that it uses just a little light is enough to:
The most distinct feature of this clock is the wheel you can use to set the alarm time. It is turnable with the thumb and pointing finger. You can turn it up or down to set the alarm time forward or backward so if any time you realise you need to wake up 15 minutes earlier than planned, you just twist it downwards for a second or two. (See below: try doing this with buttons only...) There's a spring in there somewhere so it gently resists, and pulls back to the original state when you let it go. It's just so intuitive and a pleasure to use.
There's another turnable wheel for setting the time. This is smaller, and it is not exposed to the front side. Granted, one does not set the time too often, so this being there but not in the way is just fine.
The snooze button is on the top as usual, but also on the front-top part so I reach out from bed with my underarm and press it, not needing to actually find the button (which is usually on the top-middle). Pushing it when the alarm is not on just turns on the light - for three seconds, as said above.
In order to turn the alarm itself on or off, one uses the switch on the top/front/right corner. I cannot count how many times I used this during the night without even opening my eyes to check if I turned it on/off already, or do so just then. The fact that I don't have to sense around to find the switch, then push it just enough to go to its next position but not further, is just wonderful.
Finally: it runs on batteries. Two size C ("baby" for some reason) to be precise, which is enough to run the whole thing for years, even the backlight being on 1/3 of the time. Arguably, batteries are perhaps less optimal for the environment than being wired. But there are rechargeable ones too. Also, a power outage is not an issue. Finally, good sleep during the night is important! There are very few wired alarm clocks in which I cannot hear the power adapter humming or chirping during the dead of the night.
In general virtually all other alarm clocks just have way too many buttons or switches, which make loud clicks when you use them. They are either hard to find - especially the right one among multiple - or are not meant to be used half-asleep. I despise alarm clocks that have multiple buttons to set the clock or alarm, or have multi-stop switches.
Many times there are buttons to set the hour or minute forward with one unit. Or, perhaps two buttons for setting minutes forward or backward. Or maybe four buttons (hour/min, +/-) - but then good luck trying to find the right one in the dark! In any case, if you want to set the alarm in the night, you have to press, with a loud click of course, some of these buttons multiple times to get to your desired state. If you go too far, you can start over - and god forbid this happens with forward-only buttons...
For added pain: make these buttons beep every time they are pressed! An excellent recipe to wake up everyone in the room in the dead of the night.
Multi-stop switches are even worse. I always had a hard time pushing them just enough so they jump to the next setting but not beyond. A good source of frustration, especially while being half asleep.
On some clocks there's a light sensor one can enable. If it's off, the backlight does not come automatically on. Fair enough, but then you need to push the snooze/light to check the time. If it's on, then the backlight automatically comes on when it's dark - usually with an intensity that is enough to read a book...
Unfortunately, this model is no longer available - at least Casio doesn't make them any more. I've found a trace of one unused item, in original packaging at some point (note: in 2021) but it's no longer available. Otherwise I may find claimed-to-be-new items on very shady looking websites. I'd be glad to hear if you happen to know about one (especially if it's new!).