To me the only real difference in style between SAF and Mourinho is that SAF is pragmatic when he has to be, Mourinho is pragmatic all the time. SAF prefers to play expansive and attacking football, but has learned to play defensively in Europe and some away games when it will get the result. Mourinho will happily play expansive, attacking, negative, counter attacking, defensive, park the bus, long ball, whatever he thinks will best get him the win with the resources at his disposal. Ole could be as good a shout as any for Utd manager, but I think it will all depend on the situation we are in when SAF leaves. If we are still dominant in England and near the top of Europe then maybe we would want an ex Utd player to keep us going in the same direction and just keep the trophy count ticking over whilst they learn the ropes and impose their own style. Sort of like Dalglish the first time at Liverpool or Guardiola at Barca. But if we're struggling a bit, like back in 2004, then maybe we'll need an experienced manager like Mourinho to impose his own style and turn the club around, rather than risk an inexperienced manager causing a slide.
