INTERNET HIGH FIVE!
I prefer X too. I'm not sure who my absolute fav mega is, But it's probably Banette, Pinsir, Or maybe Garchomp.

Mega Charizard Y- 8-
Mega Aerodactyl- 7
Mega Scizor- 13
Mega Gengar- 19
Mega Kangaskhan- 1
Mega Alakazam- 10
Mega Banette- 15+
Mega Venusaur- 17
Mega Aggron- 10