we used a variety of transport options in the cities we visited...
in la/
disneyland we just used the airport shuttle/disneyland resort express shuttle (operated through grayline).
in nyc we used a cab from airport to hotel, on the way back to the airport, the hotel arranged a livery car service for us (flat rate, same as the cab rate, but much nicer car/more room etc.
in orlando, we used mears shuttle service ($30 round trip pp) both too & from airport, but used a car service (through the hotel) for our trips out to florida mall etc.
in vegas, we just used cabs to/from airport as it was only 5-10 mins from mccarran airport to our hotel...
not sure if any of that helps with your destinations, but we just basically went with what we felt was cheapest/easiest for the destination and our needs. when we used the shuttle service, they had no issues with our luggage, and we had a mountain, as evidenced below: