We didn't have a bad experience at all with our shuttle or our driver. It just seemed unneccessary to prebook from home.
We speak very little Spanish and our driver spoke very little English. We were the only three in the vehicle.
The "20 minute" transfer to the resort from the airport seemed much longer. And it's quite a boring drive since there is very little to see along the way.
Had we been in one of the shuttles that takes others to the various other resorts, we would have had someone else to chat with.
We also love the looks of the folk's faces when we tell them we are going to Desire. It's pretty funny. Plus they have all sorts of questions - and they have all sorts of preconceived ideas and stories they've heard about a resort like Desire.
And, on check out, Desire will call you a cab or shuttle. It's there within what seems to be seconds as there is a taxi stand just outside the Desire property. The ride from the resort to the airport seems like only 10 minutes!