The question says how is best current manager. Does this include all what the manager has done in the past, or just as of NOW, meaning maybe the last 2 seasons...
In eiher case, I think its SAF, because at the time he took over at MUFC, the club wasnt doing that well, as a matter of fact the club was doing quite poorly, nevertheless, he made it the most successful club of the last decade. Pep Guardiola is doing an amazing job. True, the team was full of skilled players, but the morale was very down, and not only he reverted that situation, he won all competitions played that year getting 6 titles in the process, a new record holder for a season. Capello, is also a manager, that won almost everything he can, so does Lippi. Mourinho, is good there as well, I am sure he will be Portugal manager one day. And lets see how he fares there. Wenger, he is good, but not as good as the others. His Arsenal side, doesnt seem to have a consistent in reaching titles, and always somewhere in the seaoson it drops, and by the time it gets back on its feet, its too late.