It is a sight to see- worth going once, but expect traffic, because this is a popular tourist spot. (So, definitely don't plan anything during major holidays.) I've never taken the tour, but looks like it would be interesting.
I am reminded of scenes taken from movies like "Transformers", "Vegas Vacation" and "Fools Rush In." It's a massive feat of engineering, featured on the Travel Channel's shows- I forget which one, but I did see it. I still have the first pictures I snapped when I first moved here- it might still look the same- generally speaking. You can park and walk a bit and take some pictures. From what I understand there is a huge construction project that will help alleviate the traffic woes (an overpass) but not sure when completion of the project is slated (saw the story on the news recently).