I would recommend going on a week day, when they are less busy. I have been twice with a group of friends, and had very different experiences. First visit was on a relatively quiet day, and it was really good fun. Second visit was on a busy weekend, and I think it is safe to say none of us would go again.
They had made a mistake with the booking, and not allocated us any drivers. The attempt to sort this out was to squeeze us in later in the day, which messed up our plans as we had purposely booked the earliest slots possible because we had something else planned for the afternoon which we ended up having to cancel. Several of us found our rides cut short when we did finally get them, and the AMG experiences were distinctly underwhelming as there were clearly too many cars on the track at a time which meant you had to keep the speed down. But what really annoyed us was that at no point did anyone apologise for their error, and the staff seemed to think they were doing us a massive favour by cramming us in. I can understand that they were struggling to fit an additional eight people when they were clearly fully booked out for the day, but they made the mistake not us.
So my top tip is to try and go on a quieter period.