that is a loaded question ......
i use 2nd generation
Lumatek E ballasts i love them i managed to save about $11 a month too! so its not a nuge difference.
Benifits, the bulbs burn @ 95-110% of rated power, this is far beyond coil ballasts , (there are some exceptions IE pl sys. , power house)
they claim over 20% more light from the same usage, that is a fair statement
there are some really bad ones that cant handle a storm. i killed 8 future brite ballasts in one storm.
one close strike and the boards were history