Coralife customer service
They get a thumbs up from me. It was a little hard to track them down (the numbers in the product literature are wrong), but I finally called Central Aquatics' customer service dept today and left a voicemail. Got a response an hour later, and now my replacement Aqualight is on its way.
Granted, I've gotten poor life out of ballasts on two (out of two) of my Coralife fixtures so far, but at least it's good to know they'll make warranty service easy if something does go wrong.