Before he took over at Everton they were always struggling to be fair. 14th - 17th most seasons I'm in correct. In a few years Moyes took them from near the bottom of the table to a solid top table side. He done this without much money as well. That is a massive achievement.
A lot of people will point to the fact that he never won a trophy, and wouldn't be able to handle a top club that has money and should be winning trophies every year. This may well be the case, but I'd far rather we give Moyes the chance than an overseas manager who will only stay for a couple of seasons and then leave.
My main reasons for being happy with the appointment:
Aforementioned achievement with Everton
British manager
Over 10 years experience in the Premier League
Loyalty
Sir Alex's number one choice.
A lot of people may disagree with the last one, but I'd like to think Fergie knows more about football than any chief executive. If he says he sees himself in Moyes and believes he can be successful, I'd be willing to listen.
He has time to turn this around.
The short version of this answer