I'll get steelbooks if they're all that's available or the cheapest option, but I don't really go out of my way to get them, usually. Too easy to dent/scratch, even with just general wear and tear of taking on/off a shelf and rubbing against other cases on the shelf. I don't really have interest in letting them just sit there as collector's items; if I'm getting a movie, I'm getting it because I plan on watching it, likely multiple times over, so they aren't really my go-to as a result.
Big steelbook box sets can be nice, though, like this one I have:
It sits at the top of my shelf, so it isn't really rubbing/scratching against other titles the way my general one-off steelbooks are.
As far as Alien/Predator stuff goes, I don't have any steelbooks there. I have the Alien Anthology Blu-ray set, the
Prometheus 3D Blu-ray Collector's Edition, the Target edition of
Alien: Covenant on Blu-ray with the digibook replicating David's Artwork,
Alien: Covenant 4K,
Alien 4K,
Aliens 4K, the Predator Four Movie Collection 4K, and
Prey 4K. I still need to pick up the 4K release of
Prometheus. Don't have either of the AVPs and don't really feel the need to get them.