Driver was a bit early which was good since traffic was the usual slow grind. Got to airport in plenty of time to check in and not rush. Drivers are always courteous and helpful. Often travel solo, it is nice after a long flight to not have to worry about where to go for a taxi or looking for a bus or train. They meet you, take your luggage and you just follow them.
I had an experience where I arrived at my destination airport and the illegal taxi drivers were being very pushy and aggressive with me because I was alone. My Viator driver showed up and these pushy men scattered away immediately. Had I been looking for a ride on my own, this would have been a very stressful situation.