I had to replace a shoplight fixture in the basement. Got a T8 version instead of the old T12 standard. I never paid any attention to T8s before but they seem to have definite advantages. 20% less energy use, slightly more (though mostly unnoticeable) light output, slower light output decrease, smaller size. Didn't really pay attention to the pricing but I don't know why they would (if they do) cost more. I'll be replacing all my T12 fixtures with T8s when they die. That will probably only take another 10-20 years!