The premise is you board a party bus which is basically just an open air tram / safari vehicle. Then, you ride around with screens on all sides of you while a cheesy movie plays. Nothing about it screams fast cars or adventure. I think that's a big part of the let down. People go into this expecting street racing. Something similar to the end of Test Track or the old Disney car stunt show, but they don't get anything like that at all. What's worse is the queue is great, and it sets you up to expect something fast and furious, so when you get on the ride and find slow and corny instead, it's even more of a let down.
Kong isn't much better as far as the thrills go, but it makes sense, so it works. You are on a safari vehicle going through the jungle when of course things go wrong, and you have to be rescued. It's still a safari ride, but there are some real sets and animatronics, the story makes sense and is exciting and fun, and it has a great ending. With Kong you know what to expect, and you get what you are expecting, so there's no let down.