You question is a good one, but it's still subjective. It comes down to this: What things in a Pastel do you like best? The Fire can amp up contrast, & brightness. Then look at the animals over lines, lines are too general. Each line has both blah & wow factor examples.
I personally like the Fireflies that are made with high blushing animals- they seem to glow! But the high contrast animals throw some amazing babies too! I'll put up a pic of the baby I'm getting in as soon as the breeder gets me an updated post-shed pic.