I'm getting so hyped for Nov 21st.
Now I'm not too sold on Mega Sceptile, or Mega Sableye(the broken Prankster set is better imo)
Mega Altaria looks promising stepping up from being a Sdef wall to a good attacker getting Pixilate(fear the Hyper Voice!), plus being the first Dragon/Fairy is awesome.
Mega Salamence is moving out of the glass cannon set with its def boost. And with Aerilate it finally gets good Flying STAB moves!
Mega Metagross is just OP... high Speed boost, plus Attack, SpAttack, Def and Spdef, with Tough Claws. I think GF is over compensating for the loss of its Dark and Ghost resistances.
Finally Mega Lopunny gains Fighting type and Scrappy ability with a high boost to Attack and Speed, about time it will be able to use all the nice attacks it can get, and see the end of the Switcheroo sets. I only hope they bring back move tutors for Drain Punch.