Well uh, my opinions have changed a little bit.
Overrated
I *would* say Phantom's Revenge is the most overrated, but I got a ride with very poor ride conditions (not feeling the best, large crowds, early in the morning). I would also say I305 is super overrated, but as it turns out, there are a handful of people who say that it's not the best ride in the park. So, I decided to choose a ride that I've seen nothing but positive reviews of; Storm Runner at Hersheypark. I really didn't see the appeal for this ride! I only got one ride, but the ride overall was just...kinda forgettable? The launch was really good, but the rest of the ride had a rattle, was jerky, and overall just didn't do anything for me. Yeah, the layout is great, and I can see why so many people love it; I just didn't get the best ride on it I guess.
OverHATED
In my opinion, there's a difference between "Underrated" and "Overhated". Underrated is a ride that isn't talked about, but really stood out to me. Overhated is a ride that many talk about for being bad, but was better than everyone said it was for me. Those rides, for me, are Mighty Canadian Minebuster, Impulse, and Nighthawk. All 3 of these rides exceeded my expectations. I had heard many less than great things about these rides, but they all surprised me! MCMB was smoother than I expected, Impulse was overall better than I expected, and Nighthawk was more fun than I expected.
Underrated
Easily, the 2 most underrated coasters I've ever ridden are Fahrenheit at Hersheypark and Adventure Express at Kings Island. Fahrenheit is just something that works very well for me. The inversions are some of my favorites ever! It's just a very good and underrated ride for me. Adventure Express, on the other hand, is one of the most underrated night rides of all time! In the back car, every element was very whippy, and it was very smooth too! It was so good that it ended up in my Top 30 overall!