SPOILERS BELOW
With a rocky start, I think the series redeemed itself with the second and third movies. The first movie of the trilogy was just fine in my opinion, it didn't have much action, but it helped set a base for the next two movies.
Part One: 1994 was an interesting enough movie, but I only found myself scared for a few minutes, and that would be with Kate's death and the bread-cutter. Other than that one scene, I found the movie to be a little dull and confusing with the constant plot changes.
Part Two: 1978 was the best movie of the entire trilogy. One of the flaws of the first movie was that the plot seemed rushed and you could not get used to the characters. The second movie however, was much better with the backstory and explained a lot of my questions. The actors did a really good job in all three movies, but I felt like the acting was best in Part 2. This movie was gorier than Part 1 and was scarier especially with the violent deaths of Jeremy, Cindy, Alice, etc.
Part Three: 1666 was far better than 1994. Kiana Madeira (Deena) did a great job as Sarah Fier, and the hand-cutting scene with Solomon was gross and frightening. Netflix did a good job wrapping up the series up right. The ending was interesting and I am hoping for another movie soon. I think a Ruby Lane backstory would be a great movie.
Overall, I watched the trilogy because I have just gotten into horror and I wanted to start with something newer and "made for my age group" of teens, and I really liked these movies.