I don't use them. Can't afford them. Lol bit I know people who do. I know they hold their spectrums longer than other brands, so you can go longer before replacing them due to degradation. Also, they are supposed to have much "cleaner" light.

Also, as it is the popular way of recommending lighting, wattage and lumens are misleading. The par value of said lights are what counts. Unfortunately, manufacturers do not include that rating on their packaging and you need a special meter to read it.