What's the deal with backlighting?

      Backlighting requires a light under the key, a keycap with a translucent legend, and a switch that allows enough light to pass through.

      LED placement has to be just right to pass through the switch housing and not be obscured. Cherry switches are designed to let light pass on the 'south' side, ie, on the side that faces the user. This is useful for front windows for lock indicators, which go way back with Cherry boards. But if you've ever tried a switch with a window or translucent legend on the top of the keycap, you'll know that the light from a south-facing led doesn't make it to your eyes through that window. You have to position yourself directly over the keyboard to see it.

      Gamer brands figured out the way to meet consumer expectations was to flip the switch around, so the near side is now the far side. This way the LED could illuminate a shine-through legend on the top of the keycap reasonably well. Not as well as what can be done with membranes, but good enough. But keycaps are generally designed for switches that face the other way, so some thicker CYL keycaps won't fit on switches that are flipped around like this. Most shine-through caps tend to be a bit thinner and in some variety of OEM profile which is taller than Cherry.

      Because of this compatibility issue with the most popular key profile it's not common to find north-facing RGB outside of gamer brands. A good rule of thumb is that if it comes with shine-through keycaps, it has north-facing RGB. The RGB is almost always programmable, so if you want a plain white backlight you can set it that way. (Note, however, that when combining three colored LEDs to make white the effect is not perfect.)

But do you need a backlight?

      Why do you think you need one? This is a strange thing to me; nobody expected this technology until recent years. Shining extra LEDs into your eyes at all times while you're at the computer for such minimal benefit. Normal keycaps, if the colors are intelligently-chosen, are highly legible and designed to be so. In good lighting they are far more legible than shine-throughs.
Even with the lights out, the glow from a typical computer screen is more than enough to see your keycap legends clearly. And all manner of gentle lighting solutions for nighttime exist. Why insist on bundling this with the keyboard?

      Even in total darkness, if you know how to touch-type you can find your way around a keyboard without looking. So the number of genuine use cases for this technology is likely very small. Chances are, unless you are a shitty typist who uses a wireless keyboard on your couch with the lights off at night, you don't need your keys backlit.

      If backlighting is your aesthetic preference, ok. I understand this. But don't confuse matters and invite criticism by pretending this is utilitarian. You are comforted by the soft lights that emanate from your computer, it seems warm and alive. Maybe you don't want to admit this because you have snobbish feelings about gamer RGB that you learned from internet memes, and you're embarrassed to pay extra for this sort of intangible benefit. The more honest you can be with yourself, the better anons can help you find what you actually want.

      I mentioned before that MX isn't well-suited to backlighting. There are two reasons. Look at just about any picture of an RGB board and you'll see the first reason: the light bleeds a lot between the keys. Maybe someone has invented a switch that delivers the light up to the keycap without spillover and I just don't know about it, but every switch I've tried lights up the space between the keys almost as much as the legends. The backlighting on the Logitech Illuminated Keyboard I owned over ten years ago is far superior to anything I've seen from an MX board.

      It also can deliver light to legends centered in the cap, and that's the other thing MX can't do: MX backlighting only works with legends that sit at 12 o clock on the keycap, just above the center; or, with south-facing RGB, you can have shine-through legends on the front side. Other than that, not much will look acceptable.

      If after all this you still want backlighting, go ahead and ask for recommendations. But don't be surprised if anons shrug their shoulders, call you a faggot, etc