I used NAP XP Pro Series Spitfires last year and they were amazing. I shot my first doe at 10-12 yards from the ground. The WHAP sound at impact was absolutely brutal sounding, she scurried about 25 yards and got into a standing corn field. She was piled up within 50-60 yards (hard to tell as it was dark when I tracked her and she was in standing corn).
I also shot another doe with them last season this time quartering hard towards me at 32 yards. Again, had a complete pass thru, this doe only went 35 yards or so and did the death flop.
Here is an example of what the blood trail looked like on the first doe I shot with the XP Spitfires.
Like someone said earlier in the post, a blind man could follow the blood trail. At the spot of impact there was blood sprayed 3ft on either side of where she was standing, I've never gotten that kind of a blood trail shooting fixed broadheads.