Not underrated just...not used to her potential, so people think she's a joke. Underrated implies that people know what she's capable of, but think less of her. Where as most people don't realize, or know rather, that she's basically a walking, living atomic bomb.
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The only thing thats with you your whole life is complete and utter darkness.
She beats Angel (metal or feather wings), she hulk, sebastian and sage.
Rogue'll just absorb her powers unless she covers herself with something Rogue's power cant penetrate. She can turn into diamond or adamantium but Jubilee's power can probably eat away through those, probably not. Speedball, she wont be able to touch so tie.
Speedball, Rogue and Jubille take her down more often than not.
Their powers can eat through most of her forms and they all have excelent range. Her more invulnerable forms are usually limited in reach, versatility and general attack. Her best chance in these forms is to try and close in on them, but they can all BFR, keep her away and evade, specially speedball and rogue. They can drop buildings on her head and might be able to ko her even in some of the ultratough forms.
She probably takes all of the bricks though, she's too versatile for them. Angel would better fly away.