I've had good luck with Advance products. If the lifespan of the metal halide ballast you have in there now has been low, I would definitely not replace them with an oem ballast. I dont have too much experience with metal halide though. I have seen far far more fluorescent fixtures with poor ballast life, often shorter then the time it takes for the bulbs to be halfway worn out. I almost never put OEM ballasts back in any of those fixtures.
Eta: many times, by the time ballast needs to be replaced, the fixtures themselves really aren't too far behind... May want to do a cost-benefit of replacing the entire thing