I just did this last week. It was as good as can be expected. They appear to have at least 3-4 buses making nonstop, endless trips to the center. The trip took about 8 minutes. Once there, if you a member of any program (and I'm betting 95% of us on FT are) you go straight downstairs to your car.
One tip ... take the elevator. They have escalators that go directly to different floors and you can be easily confused. (Let me rephrase, I was easily confused).
