I think it all depends on timing (and a bit of luck). Sometimes, the bus was already at the airport and we simply got on and went straight to the resort. Other times, we've waited a bit at the airport (20-ish minutes) before the bus arrived, and made stops at multiple resorts before arriving at ours.
Between those options (Magical Express or Uber/Lyft), I'll always go with Magical Express. It's free, Disney-themed, free, (usually) convenient, free, and the competition has too much bad press for me to trust them. Oh, and it's free (you can't say that about too many things at Disney, so it's worth repeating
).