I will always be an HID man, in 2007 I started growing and bought 2-400 HPS systems, at that time electronic ballasts had not been out that long and were more expensive to boot. They've been out for a few years now and a lot of the bugs (glitches) have been designed out of them. I just bought a 250 HPS digital Galaxy last November and I think electronic ballasts are the way to go, a safer way to go with their shut-off circuitry design. My biggest concern these past few years while growing has always been FIRE. I'm going to retire my 2-400 HPS magnetic coil ballasts. I've always liked the 400 HPS for heat reasons and I'm looking into buying 2-400 HPS electronic ballasts to replace my 2-400 HPS magnetic coil ballasts. NextGen makes a ballast that can run both 400-and-600 HPS bulbs, and I'm seriously thinking about ordering 2 of them. At around $200 a piece and a 5 year warranty, down the road if I ever want to upsize my grow, all I'd have to do is buy just 2 - 600 HPS bulbs and press a switch. I believe in efficiency and getting my moneys worth many times over.
Also, with my power bill running through my landlord, (he delivers the power bill on rent day-because it's in his name, he said he does that because of past tenants moving out having left not paid 2-3 months of their power bill and new tenants moving in having a hard time getting power on in their name).I have to keep careful and not use massive amounts of juice as to arouse suspicion. I think electronic ballasts are the way to go, when you consider their efficiency. A 400 watt magnetic coil ballast for example uses more than just 400 watts, my SunSystems GroPro magnetic ballast uses 479 watts, and that goes for all magnetic ballasts no matter what wattage, they pull different amount depending on brand and wattage rating , but always more wattage than they say. Electronic HID is the way to grow.