my mistake. i always thought of phoenix as an upper level herald like thor or silver surfer. she was beaten by magneto before and rachael as the phoenix was a match for one of the weakest herald (frankie ray).
well it does depend on who you mean by Phoenix- if you're talking about Rachael then the stats are different and team X is beatable... I was assuming you were talking about Jean Phoenix (who did struggle at first due to the Jean persona) Phoenix when let loose is a universal elemental force that can beat a fully fed Galactus.