Colleen, easily. Misty's something of a one trick pony, while Colleen has some actual skill, and learned a few tricks from Lord Rand himself during a mind meld. Not to mention, her willpowers damned near Cap level, based on the fact she beat heroin addiction through mere meditation.
As I recall, Colleen was also the mvp against Steel Serpent (Misty got in a bionic grapple attack, but Colleen was battering him with her covered sword, until Spidey missed with his webbing and caught her sword sheath mid swing.
