I agree with BigMac on this one. I have had e-ballasts and magnetics. The e-ballasts are not the way to go IMO. If you are running a AquaController or anything that uses X-10's, the e-ballasts will make them go nuts. When I had my e-ballasts, my aquacontroller was turning everything on and off at random. I tried adding power filters,etc. nothing seemed to help. I also think that magnetic ballasts in general drive bulbs better.
Now if BigMac and I could just see eye to eye on skimmers.....hmmm.