If you want "clean" as in small and unobtrusive but want to keep your mogul bulbs then the choice will be an electronic ballast.
Electronic pros:
- can run any type of MH bulb of that wattage (SE, DE, Euro, etc, etc)
- runs cooler
- uses less electricity (a true 250W draw)
- smaller
- lighter
Electronic cons:
- more expensive than magnetic ballasts
- usually gives less PAR than magnetics when using the same bulb (less energy in = less out)
I know that Vertex just came out with some electronic ballasts at bargain basement prices. Not sure with how they perform, though.
http://www.jlaquatics.com/product/vt...e+Ballast.html