You have to remember that those of us who frequent here are a little out of the "normal" for tv owners, and understand the need for bias lights, proper calibrations, etc. and the science behind them. I'd venture to say that most tv owners don't know or care about such things so the market for Ambilights etc is a small one. Ideally, as close to 6500k and a CFI index of 90 or greater is best. However, those kinds of lights are hard to find in hardware stores, etc. Mine is rated at 5500k with an unknown CFI. Works fine for us though. Keep in mind that even the stated temperature rating might not be as accurate as one thinks. That's why some of the bias lights offered by some professional calibration services are probably better than what the DIY can put together because they can more tightly control how their bias lights are made, tested, and rated.