I think the first one is the best with little contest, and for one specific reason: every story that follows is just a repeat of the first. They do try to set up each of them in a different way, but I don’t think they were able to reach the story potential of the first one because the idea had already been done using the best ideas. The best idea for the Jurassic park series that puts it above the rest is the choice of monster. The most dangerous monster in the first book is the velociraptors. Other parts of the series have to use a different type of dinosaur, but I don’t think it any of them ever reach the same tension as the first one. The fact that they are so smart and learn throughout the movie makes it more intense (I know that other movies have velociraptor hybrids, but I think that this isn’t as interesting because it takes away the multiple raptors. The fact that they hunt in a pack is also important). The biggest let-d0wn about the Jurassic world movies is that the velociraptors are now on the side of the humans. I think it was a huge misstep. You take a really menacing group of monsters and turned them into something like a dog. (I don’t think that the first movie has the best special effects across the whole movie, but I also think that if the story isn’t that great, the best special effects in the world won’t redeem it (see Avatar).
Just my thoughts.