A towncar service meets you with your name on a sign even before you get your luggage. It then goes directly to your resort, unless you'd like to stop for groceries. Very convenient.
To use Mears transportation, on the other hand, you have to get your bags, wait for your turn to go, and then ride along as other parties are dropped off before you.
But Mears is the official shuttle and has been for years and years. You won't get cheated. Also, you're on vacation! Why worry about arriving 40 minutes or 80 minutes after you de-plane?
Families of around 4 or more people may do better with a reputable limo, such as
FL Tours. If that's your choice, good luck. In my understanding it's very competitive among the cabbies (I mean limo drivers... same thing) who are stealing fares and not picking up for the return trip. Consider that return trip when you book the "hurry-up and get there" arrival trip.
To get you to WDW a towncar is always faster than the Mears shuttle, in my opinion.
