A breath of fresh, nostalgic air as far as action movies are concerned. This is an 80s action movie through and through: characters pump out one-liners, you can see what's happening during the action scenes, the characters are all caricatures, badass stuff happens all the time, but most importantly, nearly everything is done with proper on-set effects and disguises. This alone really gives the movie an old-school edge. The predators feel appropriately heavy and grimy, punches and slashes seems to connect better, their movements seem more natural, and generally it's all very satisfying. There are a few CGI creatures that work okay, and the CGI mattes and techno-effects spruce up the movie very successfully, so as a whole I'd say it's the perfect blend of CGI and live-action.
The movie isn't perfect by any stretch of the imagination, though. Plot-wise, this is a very run-of-the-mill affair. This being Predator, it still works well and feels badass, but it's not going to stay in your head for very long (leave that to the original's tension and mystery surrounding the as-of-then unidentified predator). In other words, it's a great sequel that does all it can with what the original left it, but it can't hope to surpass it now that the mystery of what the Predator is has been lifted.
In a sentence:
A great old-school gory, campy and badass action flick that is the best sequel Predator has had thus far.