After 3 flights and 30 hours in transit and being our first night in the US, having a car waiting for you was a comfort. The only downside was that you need to contact the company upon arrival to have a car allocated. Armed only with an Australian mobile (cell) phone and no change for a public phone, and being very tired the process was a little stressful. We very soon after acquired a US cell phone for $25 which included $10 credit, so the other transfers we had booked were much easier.
When we arrived the car was NOT waiting for us. I was told that I never confirmed the reservation (which I did). Finally was told that they had a driver for us and he was waiting at terminal 3. We were at terminal 2 and were told to walk over to terminal 3! I said absolutely NOT and was transferred around again until I finally spoke to someone who asked where we were and said he'd send the driver to our terminal. The driver arrived but was NOT very nice.
We had so much trouble with the booking process. Received confirmation from viator straight away but the limo service website would not allow us to register. Email to provider for assistance was not answered. We called at international rates to confirm our booking and provider had no record. FInally, able to sort out from Chicago airport. Driver was very friendly and provided good service.