Magical Express, all the way. I don't think 3 hours is enough, personally, in some instances.
A few weeks ago we were outside, soaking up the sun, an hour before our 10am departure. The 9am bus came, offered us a lift, and we took it. It then went to POFQ, OKW, and SSR before going to the airport. After getting off, getting our luggage (our airline did not participate in RAC), checking our luggage, using the bathroom, eating a quick meal at BK, and getting through security, we were sitting at less than an hour before our flight. If we had grabbed the later bus, we would have been RUNNING...not the way I want to end my vacation.
I would much rather end my vacation relaxing at the airport than relaxing by the pool and running for my gate..