We used Magical Express on our last trip and it worked out great! Plan for it to take about 70 minutes from the time you touch down at the airport to the time you check in at the hotel.
The bus ride to the hotel was fun -- they played Disney shows & information pieces on the little mini-TV's above the seats. You can just sit back and relax.
It's a great start to a Disney vacation and it's FREE!! Better than paying for an airport shuttle. Gets you in the Disney mood.
I've read that some people had a problem with luggage taking a long time to get to the room -- but if you go straight from check-in to a meal or hit the parks for a little bit, you probably wouldn't even notice that.