Great news, i'm glad it's finally been confirmed.
He's authoritative, likes attacking football, a great coach and a winner.
Why is everybody so sure he will be a disaster?
It will be interesting to see if his fast-passing game translates from leagues where there have been one or two top teams dominating the league and the rest largely accepting their place as fodder, to a league where even on the last day, with nothing to play for, the opposition team will press hard and try to win. There are no "gimme's" in the Premier League, for sure.
Having said that, if it works even 75% effectively, United will be in the top four for much of the season. Whether they challenge for the title or not depends on a number of factors (sorting the defence, raising the goals scored, Van Gaal not exploding at Old Trafford)
A good appointment for United, but a few things have to fall into place for it work to its fullest.