In the past, everything was better — or at least simpler: if you wanted to buy an incandescent or halogen bulb, all you had to do was think about its performance, dimensions and beam angle; the properties of the light emitted were mostly fixed by the lighting principle. Even brightness was so strictly coupled to the power consumption that consumers went by watts rather than by lumens. LEDs on the other hand can be tailored for a wide variety of properties. But what are the criteria for good LED light?