What wattage are they? I've seen 600W MH with electric ballasts for like $175. I'm not sure I see the value in getting hi bay lights.
the ballasts are typically attached to the fixture and they're not designed to be quiet.
Electric ballasts are, reportedly, silent, light weight, and more energy efficient.
When, and if, I start using lights that's the way I'll go with it.

Electric ballast = electronic ballast

Both ballasts are electric.

Was that your breaches speaking willard? :P

Absolutely. I've got two MH 400w lights made from high bay ballasts. If you follow the link below you can see a few pictures I took. I removed the lens and hanger assembly and removed the ceramic mogul socket. I bought a commercial horizontal reflector that had its own mogul socket built in. I also bought a horticultural bulb. Then I wired it all up. If you use a high bay ballast, make sure it has 120volt taps if you plan to use it with standard wall power. I got the idea to do this from a guy on this website! Saved me a lot of money. You might be able to use the high bay reflector for more savings, but I wanted something better looking since this all lives in my florida room and I wanted a glass cover for extra protection.

Here is a link that might be useful: My lighting pics