The only thing a magnetic ballast has over digital is that it is cheaper. Magnetic ballasts run hotter and are much noisier, and heavier. A magnetic ballast ignites the bulb, then keeps it lit with a pre-set amount of electricity determined by a coil, core, capacitor, and ignition system. A digital ballast is able to, through circuitry, adjust the amount of electricity that is being sent to a bulb to optimize performance, which will reduce cost of running and increase the life of the bulb. It will also produce more consistent light, and has the ability to shut itself down if the bulb is not running optimally. As magnetic bulbs get older, they can flicker which can disrupt the color spectrum, as well as the overall lumens.