Funny coincidence: I was just re-reading second of Rage War books, Aliens Invasion and there was a character who theorized that Xenomorphs are smarter than most people give them credit and actually compared them to dolphins
Anyway, I like the idea of Aliens being able to comprehend science, religion or culture, potentialy having highly-organised society. Unfortunately, there's not much evidence of it in 6 Alien movies and 2 AvP ones, at least for me. Maybe they lack inteligence of a human or Predator but it doesn't neccesarily make them less of a threat in my eyes. Aliens as I see them and as they're portrayed in many stories are creatures that will always look for a weakness in its enemy's defense: using vents to navigate on board of Nostromo in Alien, crashing dropship, cutting off lights in Aliens, kinda iffy but I still think Runner was able to f**k with Golic's mind to get him to release it (if you're going by Theatrical cut it doesn't even get captured), using its own blood to escape holding cell, using liguid nitrogen against humans, creating an underwater trap to weaken humans and make them lower their guard in Resurrection, despite all their technological wonders we see in flashback sequence in AvP movie that Predators can't always contain them too, AvPR proofs it even further. There're also first AvP comic, AvP2, Mark Verheiden's Trilogy, Rogue, Phalanx etc.
Single Predator probaly would be able to kill dozen of Aliens without breaking a sweat - but as long, as there is one Alien, one facehugger, one egg - it will retreat, lick its wounds and patiently wait for an opportunity to strike back
I think it's fair to say people get the impression a lot more of them die than actually the case, and just like the expanded universe often depicts (in the past anyway) the over the top bravado of the marines then treats it as gospel truth, it often does similar things with Alien and Predator conventions including them but only understanding them at a surface level.
Agreed, It's kinda irritating how often writers miss the point of Aliens. Marines did kill bunch of Aliens, yes - but in doing so they lost half of they own men and were scared shitless. It's what I like about Aliens - you can kill an Alien, yes - but your chances to die are still high as f**k