Depends on the setup and situation, against a kakuzu and edo itachi not the greatest, more so if your using kakuzu as well. You might find it hard in real battle to get a kill before round 3, edo itachi lowers the threat that sleep has a bit since most paired ninja with kimmono itachi is not immune, plus the extra defense from the high chakra, and the fact that kakuzu y fist still lets him attack almost any round ( nothing says S*** like you using barrier to stop an edo itachi sleep just to get killed by a fist that you just buffed up). Itachi kimmno is a soft counter to eg kakuzu, it might delay but its going to have trouble shutting down if your still behind on power. Still a fun concept ninja, though not a king slayer by itself, plus we just got money ronin naruto running around ( another ninja soft countered by K itachi, though ronin is less worried about wasting chakra just to attack in his setups).