Seriously...
Darkhawk will win... although i do think Warren is better flyer in terms of experience, maneurablity and such. But that battlesuit is too much...
I havn't read anything about DH lately. What can he do that is so superior to an "apocalyptic" Archangel with a healing factor, who is probably the best atmospheric flyer in the MU? - must be cool stuff!
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THE CORPS IS MOTHER
THE CORPS IS FATHER
For instance, even if some particularly armoured battlesuits can be damaged by Warren, DH can switch to another armor in the nick of time.
Next, he can bring his heavy assault suit from the storage and unleash the dakka.
Or teleport, cloak himself, and then snipe Warren in the head...