He invented 3-3-3-1 a formation with no weaknesses. Someone told me he has a policy of not managing big clubs else could've been the most successful manager in the world right now
He's quite obviously a good manager (capable of making teams better, has also a handful gaffes in that respect like the 2002 World Cup) but also an overhyped hipster fella where the balance between style and substance is not an optimal one. I'm not sure whether he has a track record of improving players, one of the main indicators to see as an outsider - looking into a 'black box' - the quality of a manager. In europe his best finishes have been 4th, 10th and 12th with a club team. In the domestic cups he reached once a final but beyond that never higher as the last 16 (once) and then last 32. In continental games once the final (well done) but otherwise stuck at the 4th round or worse. His national team career is also patchy at best. His continental record has not the consistency of a Mourinho (most CL semi finals ever), Cruijff (6 finals in 10 seasons), Eriksson, Trap, Fergie etc. with teams of different contexts, types and sizes. That his 3-3-3-1 is so special; I don't know. Those lines don't stay 'flat'. In practice it is not very dissimilar to the 3-4-3 diamond that has been suitable to many relatively flexible pressing and possessing teams.