I have a Satechi X3 with backlighting - needed one keyboard for home and work machines, as well as a numeric keypad. I have an older Apple Bluetooth keyboard, the kind that takes 2x AA, and much prefer the key feel on that keyboard, but it misses out on these features.
Anyway, the reason I bring up the Satechi X3 is that it has backlighting. Working from afternoon into evening, especially in winter, the backlighting was definitely helpful in finding non-touch typing keys. I spend a lot of time in SQL, and being able to find the "/*" combination as sunlight begins to fade is useful, for example. Eventually I'll turn on the room lights, but having the backlight is definitely helpful.
That said, the implementation on the Satechi isn't the greatest - I see much more light spill coming out from under the edges of the keys than I do from the keycaps, making it a bit messier - perhaps reminiscent of early aluminum PowerBook backlight implementations.