Well, that's obvious, Sabertooth is the only one that has been an Avengers in that group, so of course he is the good guy; after all, we all learned in AvX that the X-men are a evil cult of psychos that worship a malevolent and extremely destructive cosmic forcé.
Im totally calling that is going to be revealed that Medusa is actually Jean Grey posing as Medusa; or that we are going to meet the child from the future of Cyclops and Crystal.
Well, i wouldnt hate crossover so much if Marvel stopped using the X-men as the villains.
Really, since when they struggle to coexist with the normal humans ?.