My favorite so far is the AvP neca aliens. My other Neca ones are a bit janky but besides some slight looseness those ones feel really solid.
I like my Revoltech but it's awkward, and my only experience with the Hiya Toys one is the really shitty old QC. I like my newer Predator, but haven't shipped my Neomorph yet so can't speak on it.
It seems like the Lanard stuff is pretty great if you can stand the funky colors and limited articulation.