Warning: SPOILERS for Dark Web: X-Men #1
The X-Men and the Avengers are two of Marvel's most memorable superhero teams, but one group's battle cry trumps the other in one way. Both teams are based in New York, have a variety of superheroes, and have members that even intersect; Avengers have joined the X-Men and vice versa on occasion (when the groups weren't fighting each other). But Dark Web: X-Men #1 proves Marvel's mutants have the edge over the Avengers in one important aspect.
Both teams originated in the 60s and were created by Stan Lee and Jack Kirby, but many of the similarities end there. The X-Men emerged as a team before the Avengers, who were a mix of solo heroes (Iron Man, Thor, Hulk, Ant-Man and the Wasp) long before joining forces. Additionally, while the Avengers received good publicity from the start and were always hailed as superheroes, the X-Men dealt with the worst humanity had to offer in the form of anti-mutant protestors, prejudice and even government-sponsored efforts to separate mutants from humans.
In Dark Web: X-Men #1, written by Gerry Duggan with art by Rod Reis, the X-Men wander around New York City during Christmastime when the events of the Dark Web event take hold (seen in the Spider-Man series in more detail). Suddenly, inanimate objects across the city began to come to life, appearing as massive monsters with fangs who want nothing more than to eat civilians. Jean Grey, the former Phoenix, gathers the mutants around her and telepathically shouts "To me, my X-Men!", the standard battle cry of the leader of the mutant team.
Why "To Me, My X-Men" Beats "Avengers Assemble"
"To me, my X-Men" is essentially the X-Men's version of "Avengers assemble", but it carries a different meaning. The battle cry of the Avengers is usually a call to arms, and a way for all the separate heroes of the team to come together (as many of them have separate careers as crimefighters and even separate books, such as Thor and Captain America). The cry of the X-Men calls for the heroes on the same team to rally behind one, singular leader. This is usually Professor X, but it can also be Cyclops as a leader and in recent years, Jean Grey.
Whatever the case, one final difference makes a profound impact: the X-Men call is usually never heard. It began as a telepathic cry and both Jean Grey and Professor Xavier use it as such. This means that the Avengers are usually visible when coming together, but no one can hear the X-Men rally until they're already a single unit.