There is no ranked, competitive multiplayer in Halo 4. I have not read a single review yet that mentions this fact.
Real text conversation with Chad (from the podcast), an old friend of ours who has been playing Halo with Dan and I since Halo 1.
Dan: Don't buy Halo 4
Chad: That bad?
Dan: No ranked multiplayer
Chad: Yeah, never buying it. That's all I play