I voted Other because I don't think that many of the X-Men can pull off their own movies, they just don't have enough interesting backstories and appeal. It probably was a big reason why Avengers worked but then again Avengers are an allstar team so this concept works better for them because they have life outside of Avengers and have their own personal villains but X-Men and FF were created as a team and they don't have that much adventures outside of the team except for Wolverine. For FF they are pretty small and tight group so a team movie works for them but X-Men have so many favorite characters. And other than Wolverine's past and Xavier and Mags backstories before the X-Men there aren't many core characters that could star in their own movie. Sure there might be Cable and Deadpool but they aren't the most iconic core X-Men. So the best way to go that I can think of is to make multiple team movies and in all of them they should just concentrate on few of the characters.