I love that this turned into a "which is worse?" contest. So I'll give my personal list, from top to bottom:
AVP:R - ridiculous, bad setting, like very bad setting but I find fun moments personally, some cool Alien on Predator action even though the Aliens weren't treated with respect. Except that Aliens on Earth in the present day in a town, nothing too lore breaking. That's a plus.
A:CM - even more ridiculous, but I don't completely hate it cause it's a game and not a movie, basically all the reasons HuDaFuK has given, but I did enjoy the story DLC somewhat and I had a blast with the multiplayer while it was still alive. Bug Hunt is also fun, spent many hours of my life with this game. That's why I'll call it trash, but fun trash. The Hicks thing was trash, though the Turk gag we got out of it is worth it. Sci Fi settings are cool, the atmosphere was nice, but the Sulaco, Hicks and Hadley's Hope was lore breaking. Can't take it seriously canon.
The Predator - I'm not even gonna repeat all the problems I had with it, but in short. I had no fun in watching it and have no desire to rewatch it which is a first for me. Kinda/almost lore breaking stuff, the retcon they tried was almost insulting and that legendary ending with it's now infamous alternative versions were hilarious and oh so sad at the same time.
Of course, just my opinion riddled with personal biases.
