Depends on the circumstances: in a toe-to-toe beat-down, I'd go with CM, 6/10; if it's a more intricate fight, not intended to be resolved in a few moments, J'onn *might* be able to edge Billy out, via versatility and possible mental manipulation (though Solomon's Wisdom provides CM with a degree of resistance, similar to Diana's Wisdom of Athena) giving J'onn 6/10 for circumstances. Guess that overall flushes out to a 5/10 split.