If you are in a state where the cops are not a concern, go for the pretty boxes (If you got it like that). BUT if you don't live in a 420 friendly state:
All my lights were salvaged HID lights from a factory/foundry that was demolished here. All magnetic ballasts. Aside from one or 2 that had a "buzz" (LOL), they worked like a champ. 1000 watts is 1000watts, whether it's digital or magnetic, so I don't see lower operating costs. Less heat I'll go for, and maybe quicker start up time, but I believe that's more a function of the bulb. I change my bulbs every year regardless, so extended bulb life would be a non issue. I had 8 1K lights when the cops came in. My opinion is why spend a whole lot of money that the cops are gonna take if the worst happens? If you got it like that and can take a hit like that, go for the digitals. I'm pissed enough they got my fancy aircooled sun systems hoods!!!
God forbid anyone should go thru that, but the reality is we all face it. Why risk losing more than you have to when the less expensive alternative works just fine? Craigslist usually has tons of used HID lights.