1. Predator.
It has a balance to it that just works.
2. Predator 2.
Cheesy 80s goodness with some iconic scenes and one-liners.
3. Predators/Prey
The two are tied at the moment.
Both of them have amazing concepts. Prey is directed better, but the odd bits are highlighted by the fact it takes itself dead serious. Predators has somewhat the opposite issue, where some of the corniness detracts from the amazing lore additions and action. I wish Predators had a higher budget and I wish Prey had maybe a year longer to cook before release.
4. The Predator.
It felt like it was made by someone who actively despised the franchise, which is tragic because I know that isn't so. I was so excited for it and got burned. There are some genuinely good parts to it, but they are few and far between. They needed a better writer. I just thank god they didn't go with the original script, which seemed more like a saturday morning cartoon designed to sell toys.