Well, along with Sinister, those are the top three Mutant champs out there, especially for dual threat. Jean is a better defender than Onslaught if your opponent doesn't have reverse controls counter. But otherwise Onslaught is a better defender by far.
As far as attack, they're similar, can both counter thorns (since Jean is awakened). But Onslaught needs to land those unstunned heavies constantly, whereas Jean just needs to land one. You really can't go wrong with either.
I had the same option today and I went with Jean Grey and I have zero regrets, she’s so much fun and easier to play than onslaught for me personally (could never get him down but I have him at R3 still for defense)
Comments
Jean is a better defender than Onslaught if your opponent doesn't have reverse controls counter.
But otherwise Onslaught is a better defender by far.
As far as attack, they're similar, can both counter thorns (since Jean is awakened).
But Onslaught needs to land those unstunned heavies constantly, whereas Jean just needs to land one.
You really can't go wrong with either.
R4 Jean, Spiderwoman, and Yelena (not shown in this pic) today