mega Metagross is one of the most powerful and versatile wallbreakers of the tier, with a large movepool phenomenal and statistics, as well as having an excellent typing, has a decent speed, amazing bulk, this mechanical beast covers very important roles in a team is a great and unexpected pursuit trapper, is a great revenge killer, good and perhaps the best fairy killer of ou, is controlled by mega Scizor, jirachi (except earthquake uses), slowking, Skarmory (if you do not run T.punch), slowbro and mega slowbro , Ferrothorn and Heatran (if you have not hammer harm or earthquake in this case for Heatran); However, despite having many controls, it is still a very dangerous pokemon, because many builds you dimenticanmo totlamente of its existence; good teammate for mega Metagross are in a nutshell:
Wallbreakers with a large movepool, Manaphy, Thundurus, Nidoking, Hydreigon, are all great partners who threaten the common counters of gross, using their large movepool can threaten many threats, so this makes it easy to build up mega Metagross around; other good partners for mega Metagross are Keldeo, Volcanion, raikou, Rotom-W, Tang, Serperior, some pursuit trapper as Band Weavile, Bisharp, band Ttar, that threaten bulky psychic as slowking and slowbro;
Once Metagross was the best pokemon of the tier, in early Oras to be clear, I now think that the metagame is in his favor, because it is a threat underestimated because it is still uncommon, also thanks to the drop of Hippo is even more easy to show BoltBeam the set and make out tankchomp / lando-t + bulky water, moreover at a time when clef is the best pokemon of the moment i think Metagross is the best choice to send him out, Metagross loves volturn support, as indeed they love it all wallbreakers, volturn helps metagross to put pressure on the offensive team and balance.
the most common sets are: BoltBeam, this set runs meteormash, more powerful stab that Metagross owns, but iron head is a good replacement if you do not want to risk the mash miss, but you lose power, Thunder punch, very useful against slowking, SPD skarm, manaphy, Keldeo, ice punch, more important move for this set is capable of threatening Landorus and tankchomp incoming, it is a good move to eliminate latios, mega Latias, Dragonite finally pursuit, useful to trap latios, Latias; AoA, this is the typical set of Metagross, runs meteor mash, zen headubutt, useful stab move to eliminate mega venu, Breloom, Keldeo, mega lopunny, and it is good to use against rotom-w failing to have a good chance of 2HKO after rocks, hammer harm, useful as I said before beating Excadrill, Heatran, Ferrothorn, grass knot, very beneficial move against hippo, Gastrodon, seismitoad, mega swampert, Quagsire; Rock polish, this set is aimed to eliminate offensive teams, usually you run the nature adamant to have a lot of strength, and using this set: meteor mash, zen headbutt, hammer arm, but a variant could be meteor mash, thunder punch / ice punch, hammer arm, and indfine rock polish, Metagross that leads to an impressive speed, which overcomes Excadrill in the sand and Kingdra in the rain (just to give an example), this set looks very scary.
in a while I will present mega Metagross + Nidoking bulky offense, later ^^