Absolutely breathtaking!
Meh. The fee is not very high ($5), but after spending 2 days hiking around in the Redwood National and State Parks, visiting the Drive Thru Tree felt like the Disneyland version of the redwood forest. We ended up sitting in the line to drive through the tree for about 45 minutes while people either got their cars stuck or had to take a million different pictures of themselves with the tree. Save yourself the hassle and go visit the Avenue of Giants, which is free, not very far away, has way fewer people, and has a bunch of trees that are similar in size to the Drive Thru Tree. You can't drive through any of them, but it is overall a much more worthwhile experience.