I have the Mega Diancie chain, and let me tell you: the HP is horrid on her. Diancie EX: 140 HP! Mega Diancie: 190 HP! AND Mega Mawile chain isn't much different. The Mega Mawile has the same HP as Mega Diancie, but the EX has 10 higher than Diancie. At least I can incorporate two fairy megas in my deck.. As for Mega Aerodactyl, well... he's not very good. YET. Once they come out, we can make strategies for them and they could be the best megas ever.. or not! Coming back to Mega Mawile, her attacks are being generous. The energy costs are too low for such good attacks! I mean, Diancie is better because on her attack it states: Diamond Storm [F] [F] [C] 100 damage “During your opponent’s next turn, prevent all damage done to each of your Pokémon from your opponent’s Pokémon-EX. (If this Pokémon is no longer your Active Pokémon, this effect ends.)” Mega Diancie is better.