I'm surprised so many people don't understand this...
The anbu are far stronger than any ordinary jounin. In fact, Anbu are specially picked because of special talents that they possess above the ordinary fodder in the village.
Those saying Asuma, Kurenai, etc are better than Anbu clearer have no clue what they're talking about.
Kakashi - Ex Anbu, shits on every jounin in the village, and was in fact called for kage
Itachi - Nothing more needs to be said
Fuu - He and torune were among the very few people who've ever hit obito. Guess who else hit obito? Hokage-Minato, S Class-Konan and a combination of Jin naruto, Jin Bee, Hokage select kakashi and Jounin guy. Fuu's abilities alone laugh at the other jounin in the village
Torune - Same as above. Once he removes his clothes, you're dead if you ever engage in taijutsu
Yamato - He shits on every jounin in konoha bar Kakashi. Nothing more needs to be said.
Sai - Easily one of the strongest members of K12
Orochimaru - Ex Anbu
Because NAruto and Sasuke, who are 2 genin, some how surpassed every single ninja in the show, that doesn't mean that the anbu failed. So, because they couldn't protect the hokage from an ex-anbu, ex-root, ex-akatsuki, hokage-select with a Jin at his disposal and 4 Genetically altered lackeys, the anbu now suck? Ok then...