A big misconception I see here is that Machamp can't handle M Mewtwo which isn't the truth the attack of M Mewtwo doesn't get doubled for weakness. Neither does dmg change of course leaving just the first attack which isn't gonna be enough to take out Machamp. A fury belted Machamp requires 7 total energy to OHKO. A smart Machamp player wont have more than two until the third is needed so Machamp becomes a tough out for Mewtwo. Garb is a threat to the deck due of course but if you can keep those off the board its a nightmare matchup for Mewtwo. Overall I think it's slightly in Machamp's favor.
Scizor is a favorable matchup as Machamp can ohko Scizor and not vice versa. A typical Scizor match for me involves a 4-2 prize trade.
The bigger problems are of course the OHKO decks. Mega Ray is unfavorable but Carbink does big work here. Rainbow road is close to an auto loss. M Gardevoir STS also of course presents big problems.
Overall I think the deck is a solid tier two status but could become an issue as much of the hate for Mewtwo decks will also effect it.
Here's my current list if anyone wants to test.
****** Pokémon Trading Card Game Deck List ******
##Pokémon - 14
* 2 Shaymin-EX ROS 77
* 2 Carbink BREAK FAC 51
* 2 Carbink FAC 50
* 3 Machamp-EX AOR 37
* 1 Zygarde-EX PR-XY XY151
* 2 Spinarak AOR 5
* 2 Ariados AOR 6
##Trainer Cards - 34
* 4 Trainers' Mail ROS 92
* 2 Lysandre FLF 90
* 1 Super Rod BKT 149
* 2 Scorched Earth PRC 138
* 4 Ultra Ball FLF 99
* 1 Escape Rope PRC 127
* 1 Olympia GEN 66
* 3 Max Elixir BKP 102
* 3 Fighting Fury Belt BKP 99
* 2 N FAC 105
* 1 Hex Maniac AOR 75
* 2 Float Stone BKT 137
* 4 Professor Sycamore XY 122
* 4 VS Seeker PHF 109
##Energy - 12
* 4 Strong Energy FFI 104
* 8 Fighting Energy BLWEnergy 3
Total Cards - 60
****** Deck List Generated by the Pokémon TCG Online
www.pokemon.com/TCGO ******