We had a lot of fun on the tour and due to our Viator reservation we had no issues obtaining our cars on a very busy weekend. The speakers in our car were it working properly do we had some problems navigating with the GPS but we made it. My kids really enjoyed it and made for a memorable day.
Make sure your GPS is working before you leave. Once we had the hang of it and were comfortable, this GoCar is the BEST thing we did during our 5 day stay in SFO. We have 2 kids; 17 and 14 and they said it was the best tour they have ever had over all the year's of vacations. I thought 3 hours would be too long but we could have done it for 8 hours and never been tired of it. Everyone was taking pictures of us and the Northern Beach Tour or Red line was GREAT.