As far as I know, the black has a urethane/raective blend in the coverstock. It is VERY durable, which makes me think it is closer to urethane than a real solid reactive. The burgundy one is supposed to have a "real" reactive coverstock, that mocks a urethane reaction - early read of the lane, not jumpy, continous curve. Sadly, I never saw both next to each other in action.
Core in both is the original Hammer core which was used in most (early) Blades. Since it has a low RG and medium differential, I'd rather drill it for length with a high pin - but that's me, and my experience with the black one which I really love (and which is a surprisingly strong ball, great on light oil).
--------------------

DizzyFugu - Reporting from Germany
Team X website & more about me
"Put some make-up on your face
 Make this world a better place!"
Kahimi Karie, 'Good morning world'

I dont have either PH's but Ive watched a guy throwing the Burgundy in our league.
Seems to be a fair bit stronger than its advertised to be.When the lanes are dryish, this guy always goes to a Power Groove.(Greenish color).Much smoother than the Burganduy for him...looks about 5-6 boards difference to me.
--------------------
Ambition is a poor excuse for not having enough sense to be lazy.......