I think Fergie is a bit like Marmite - you love him or hate him.
But with Fergie, I go back and forth. Sometimes I love the bloke because he is a wizard, and sometimes he gets on my nerves. I love the way he handles his players, the way he publicly admits to dealing with problem players (Like when he says "they'll be dealt with" etc...) and if I'm honest, I like the way he plays mind games with everyone. I like the way he never goes into a smaller game (like FA cup matches) thinking they're going to win, he always 'bigs up' the other team and pays them respect.
I coach/manage a school football team, and when we're winning I'm always thinking "how long's left?!" and "how much longer is he going to add on?" and I often ask. When we're losing, I find myself saying "there has to be more added time!" I'm competitive and I want to win every game I play/manage. Fergie has millions of pounds riding on each point.
It's not exactly cheating, he's just using his expertise and mind games to try and win more matches. I agree, it can be infuriating if you're on the opposite team though.