I brought this keyboard for the back-lit keys.
1. The key back lighting has a really bad flicker to it, making it hard to look at the keyboard.
2. The key sounds are not a s nice as other mechanical keyboards.
3. The key back-lighting programming is not flexible enough. e.g. I cannot find a way to change the lighting on the CAPS lock, Num lock or Scroll lock keys depending on their states.
4. The Logitech drivers a bit fragmented and not very intuitive. Multiple drivers are needed for different devices.