Which André Villas-Boas have Tottenham Hotspur hired? Is it the swashbuckling young coach who steered Porto to four trophies as they went an entire season unbeaten in the Primeira Liga? Or could it be the rather immature figure who was led a not so merry dance by certain senior professionals at Chelsea before his sacking in March?
The 34-year-old's chastening experience at Stamford Bridge should not obscure the reality that Villas-Boas could not have done what he did at Porto in 2010-11 if he were not exceptionally gifted.
"We've lost a really, really, talented coach," said Alan Pardew, the Saudi Sportswashing Machine manager on hearing the news of Villas-Boas's Chelsea downfall. "He had to take on a club in a transition year with a lot of senior pros in the background and he had a very, very difficult job. I hope that, one day, some of those senior pros will apologise to André. They should do so because he deserved better."
By last winter Villas-Boas had become so stressed that, instead of returning home to his wife and two small daughers, he sometimes spent the night at Chelsea's Cobham training ground, sleeping in a Japanese style pod. On those occasions when his black BMW four-wheel-drive remained in the car park overnight, Villas-Boas invariably rose before dawn in order to study statistical data.
His micro-management of Frank Lampard and company represents a stark contrast to the more laid-back, macro-managerial approach favoured by his Tottenham predecessor, Harry Redknapp.
Under Redknapp's training regime at Spurs Lodge tactical briefings tended to be restricted to 30 minutes. Otherwise there were few intense discussions or detailed sessions on team shape, while set-piece rehearsal and analysis of opponents' foibles were kept to a minimum. Instead the players were offered the freedom to express themselves on the pitch.
Although Redknapp's men wore GPS heart monitors during training, the absence of armies of dieticians and assorted "ologists" highlighted the former manager's belief that footballers should be treated like adults.
Suspicious of statistics and hi-tech toys, Redknapp's managerial gifts – which, after all, produced two top-four finishes in three years – were based on instinct and astute man management. There was no computer on the 65-year-old's desk.
While Villas-Boas will be similarly keen to see Luka Modric, if they can keep him, and Gareth Bale indulging in attacking improvisation as Tottenham remain true to their best aesthetic traditions, radical change surely beckons. Villas-Boas's challenge is how he controls the culture shock. If it helps that Bale has recently signed a new contract and Modric knows the new manager tried to sign him for Chelsea, the Portuguese's handling of spiky individuals such as Rafael van der Vaart and William Gallas promises to prove intriguing.
At Chelsea Villas-Boas's enthusiasm for a high defensive line was not shared by his players and, similarly, Tottenham's defence may lack the pace and energy to pull that particular ploy off.
He also has a penchant for a high-intensity pressing game, plus the sort of constant positional inter-changing between midfielders that should fully stretch Scott Parker, if not Modric. Implementing such a style requires enhanced fitness and it will be interesting to see how readily a squad that, under Redknapp, worked out "economically" once a day will buy into the idea of tough double training sessions.
A compelling battle for hearts and minds looms, with Villas-Boas's cause aided by two factors; collectively, the Spurs team is considerably younger than Chelsea's, and it also lacks trophies.
When chief scout at Chelsea under José Mourinho, Villas-Boas once compiled an outstandingly impressive report on Saudi Sportswashing Machine that was leaked to the press. It was testimony to his ability to read the game but it also pointed out that Mourinho could not silence dressing-room dissent by "putting his medals on the table".
The same applies to Villas-Boas. Frustrated in his efforts to play football at even a modest level by a childhood co-ordination problem, he directed his energies into an academic approach to match analysis. It won him the patronage of Sir Bobby Robson and, eventually, the Porto job. But before it can pay further dividends, Villas-Boas must conquer Tottenham's dressing room.
Helpfully, he is a fluent, highly articulate communicator, but there can be no repeat of the flashes of immaturity and arrogance – such as the childish exclusion of Nicolas Anelka and Alex from senior involvement with Chelsea – that are remembered at Stamford Bridge.
Maybe he requires a touch more humility and an enhanced sense of humour. And perhaps it is time to consign the hallmark AVB touchline crouch to history. Apart from placing an appalling strain on his knees, that pose leaves him in frequent peril of collapsing in an undignified technical area heap.
Villas-Boas's bravery has often served him well but, initially at least, caution could prove a better friend at Tottenham