He's right... it would seem like two heavy hitters would be good since you can combo it, however it is riddled with weaknesses. Both suck against special attackers, and a mixape tears it apart in two turns. The Metagross/Gengar (or Spiritomb) combo is over played to an extent... and the fact that Gengar can go down in one shot from a Weavile or Alakazam. Not too shabby tho, give Metagross Earthquake while you're at it and you should do fine (another nifty trick with this is to let Gengar use Destiny bond on sumthing that would pose a big problem like Shuckle, Dusknoir, or another wall/staller and then have Metagross kill it with Psychic. Not too conventional, but it works in a tight spot).