Blood's burst is > than unholy's, but it is still behind on single target fights lasting longer than say... 3 minutes? As blood the first 30 seconds of NRB had me around 14kish dps, but then it fell like a rock before settling around 6.5k -7k by the end of the fight.
As unholy the initial burst was nowhere near as a big, but a significantly steadier 7.5-8k dps.
If you believe me go smack a target dummy for a bit and you'll see the difference.