I have been to Cabo twice in the past month. The first time, I used Transcabo for my airport transfer. They were fantastic. Easy to locate when you exit the terminal, and we were on the road in less than 10 minutes after checking in with them. I would highly recommend using them.
On my trip last week, Gray Line was included in the package deal. After we exited the terminal, we waited close to an hour before we were finally put in a shuttle. Before that, there seemed to be some confusion on the part of Gray Line, and they were very disorganized. I wasn't too bothered by it though, since the weather was incredible, and I was able to drink a cold beer while I waited.
Anyway, we were scheduled to be picked up at 9:40am on 3/31. I followed the instructions on the vouchers, and called Gray Line to confirm my reservation 72 hours beforehand. They said I was all set. On 3/30, at around noon, we got a call from the concierge at the PBSB, saying that Gray Line was in the lobby waiting for us. I told her we weren't leaving until 3/31. So, she put the Gray Line rep on the phone with me. He was very confused, and told me I made my reservation for 3/30. It clearly stated on my sheet that I was leaving 3/31, and they would be picking me up at 9:40. He seemed very frustrated. After I gave him all of the info on my sheet, along with the confirmation number, and the name of who I talked to when I confirmed, he finally admitted they made a mistake. He assured me they would be there on 3/31 to pick me up. After I got off the phone with him, I noticed the time. It was WAY past 9:40am. If we had really been leaving on 3/30, we would have missed our flight. That concerned me a bit.
On 3/31, we were outside of the lobby at 9:40am waiting for Gray Line. We waited close to an hour, and they never showed. So, I went inside and had the concierge call them. They told her they came at 9:40, and we weren't there, so they left. This is complete BS. We were outside of the lobby at 9:40 sharp. They did not show. And, I found it to be very strange that they had the concierge call me the day before when they mistakenly came to pick us up and we weren't there. But, this time, they just left? I'm not buying it. Anyway, we ended up having to pay for a shuttle to the airport, since Gray Line stiffed us.
Bottom line is, I would NEVER consider using Gray Line again. If you book through Expedia, or the PB Resorts website, it gives you an option to purchase your transfers through Gray Line as part of the package. I would advise that you decline, and book through Transcabo separately. Wish we would have.