Quote Originally Posted by jamstigator
I have a 400 watt digital ballast and a 1,000 watt magnetic ballast. I would have bought a digital ballast for the 1,000 watt unit, but they were either very new at that time, or they were only available in 240v versions (which doesn't work for me). The biggest advantages of digital ballasts are: they have few if any moving parts so there's less to break down over time; they are basically absolutely quiet, no hum; they generate less heat than magnetic ballasts (always a factor); they consume less energy for the same amount of light generated; they strobe their light at much higher frequencies than magnetic ballasts which the plants seem to like better. (Could be wrong about the latter, but that's what it looks like to me.)

So, all-in-all, yes, I do think they are worth it. Anywhere you're going to use an HID lamp, I'd definitely consider attaching the lamp to a digital ballast. I plan on buying a 600 watt digital ballast (or two) to replace my 1,000 watt magnetic ballast, and just keep the 1,000-watter around as an emergency spare.
Wait a minute, I thought a digitial ballast was simply that the ballast allows both HPS and MH bulbs....is this true???