So I'm a bit stuck right now. I'm wanting to buy a standard deck to play but I just can't decide. There's M Mewtwo Y, Greninja break and an interesting deck I saw. The M Gardevoir (Generations)/ Xerneas Break. I have played the Gardevoir deck on PTCGO and it seems to work very well against other decks that aren't as "good" I guess you could say. Against things like M Mewtwo Y and Greninja Break/Talonflame I just get annihilated because of the semi-slow set up. So if someone could help me make a decision what the best deck to run would be great 
I'm mostly looking for a deck to run at the most 2 Shaymins preferably only 1. So basically no M Rayquaza decks
M Gardevoir/ Xerneas Break
#Pokémon - 14
* 1 Shaymin-EX ROS 106
* 4 Gardevoir-EX STS 116
* 3 M Gardevoir-EX GEN 131
* 2 Xerneas BREAK STS 82
* 4 Xerneas XY 96
#Trainer Cards - 35
* 4 Fairy Garden XY 117
* 4 Professor Sycamore STS 114
* 1 Town Map BKT 150
* 1 Skyla BKP 122
* 1 Super Rod NVI 95
* 4 Ultra Ball FLF 99
* 1 Brock's Grit EVO 107
* 4 VS Seeker ROS 110
* 3 Gardevoir Spirit Link PRC 130
* 4 N FAC 105
* 2 Lysandre FLF 104
* 2 Enhanced Hammer PHF 94
* 4 Max Elixir BKP 102
#Energy - 11
* 11 Fairy Energy Energy 9
Total Cards - 60
Again, thank you
I'm mostly looking for a deck to run at the most 2 Shaymins preferably only 1. So basically no M Rayquaza decks M Gardevoir/ Xerneas Break
#Pokémon - 14
* 1 Shaymin-EX ROS 106
* 4 Gardevoir-EX STS 116
* 3 M Gardevoir-EX GEN 131
* 2 Xerneas BREAK STS 82
* 4 Xerneas XY 96
#Trainer Cards - 35
* 4 Fairy Garden XY 117
* 4 Professor Sycamore STS 114
* 1 Town Map BKT 150
* 1 Skyla BKP 122
* 1 Super Rod NVI 95
* 4 Ultra Ball FLF 99
* 1 Brock's Grit EVO 107
* 4 VS Seeker ROS 110
* 3 Gardevoir Spirit Link PRC 130
* 4 N FAC 105
* 2 Lysandre FLF 104
* 2 Enhanced Hammer PHF 94
* 4 Max Elixir BKP 102
#Energy - 11
* 11 Fairy Energy Energy 9
Total Cards - 60
Again, thank you