Aviv is spot on. LEDs aren't full spectrum light like an HMI and don't have the color spread of tungsten or Kinos. As such, they always look a little sterile to most folks. Backlight, rim or fill is generally not an issue but you may be less than thrilled if you try to key with an LED as the sole light source. Generally, I never use purely production light on an interview nor do I use just one color temperature. Most often we are augmenting what's there whether it be a table lamp, windows or really any other source. Every job is different but I think you'll be pleased with LEDs if you can mix in some other types and temperatures of light.
